“high-risk” percutaneous transluminal coronary angioplasty

5
"High-Risk" PercutaneousTransluminal Coronary Angioplasty GEOFFREY O. HARTZLER, MD, BARRY D. RUTHERFORD, MD, DAVID R. McCONAHAY, MD, WARREN L. JOHNSON, MD, and LEE V. GIORGI, MD Of 6,500 percutaneous transluminal coronary angio- plasty procedures performed between June 1980 and June 1987, 3,501 (1,604 single lesion and 1,897 multiple lesion) were performed in "low-risk" patients with a procedure-related mortality of 0.2 to 0.3%. In comparison, several clinical variables were identified that increased procedural risk by up to 50-fold. These factors include left main dilatation (n = 103, mortality 3.9% ), left main equivalent di- latation (n = 77, mortality 2.6%), ejection fraction <40% (n = 664, mortality 2.7%), age >70 years (n = 1,038, mortality 1.4%), dilatation of all 3 ves- sels (n = 305, mortality 1.3%), combined diagnos- tic catheterization and angioplasty for unstable angi- na (n = 193, mortality 1.5%), and percutaneous transluminal coronary angiopiasty for acute myocar- dial infarction (n = 446, mortality 8.5%). Important considerations in the selection and management of these high-risk patients are discussed. (Am J Cardiol 1988;61:33G-37G) ~n experienced centers, percutaneous transluminal coronary angioplasty (PTCA) is now routinely per- formed in patients who had previously been consid- ered unsuitable for the procedure because of concerns about procedural success, increased procedural mor- bidity and mortality or unfavorable late outcome. This "high-risk" group has traditionally included patients with multiple vessel disease, multiple lesion dilata- tion, advanced age, prior coronary bypass surgery, poor left ventricular function, and left main disease requiring dilatation. 1 This report describes the results of angioplasty in patients with these characteristics and emphasizes im- portant procedural aspects. Patients (Table I) From June 1980 through June 1987, 6,500 proce- dures were performed at the Mid America Heart Insti- tute in Kansas City, Missouri. Of 13,805 stenoses at- tempted, primary success, defined as >_20% reduction in stenosis diameter and _<50% residual diameter nar- rowing was achieved in 94%. Complications included transmural myocardial in- farction in 0.5% and urgent bypass surgery in 1.7%. From Medical Plaza II-20, Kansas City, Missouri. Address for reprints: Geoffrey O. Hartzler, MD, Medical Plaza II-20, 4320 Wornall Road, Kansas City, Missouri 6411. With the exclusion of patients who presented with acute myocardial infarction, the procedural mortality was 0.7%. If patients >_70 years of age or with poor left ventricular function, prior bypass surgery and left main coronary disease are also excluded, 1,604 pa- tients who underwent single lesion PTCA had a pro- cedural mortality of 0.3%, and 1,897 patients who underwent multiple lesions PTCA had a procedural mortality of 0.2"/o (difference not significant]. Results in these "low-risk" groups provide a refer- ence standard for the subsequent discussion. The sub- sets described are not mutually exclusive. Analysis of Percutaneous Transluminal Coronary Angioplasty (PTCA) and High-Risk Subsets Left main PTCA: One-hundred three procedures (1.6%) included elective dilatation of the left main cor- onary artery. The mean age of the patients in this group was 62 years, and 24% had poor left ventricular func- tion defined as an ejection fraction of _<40"/o. Seventy- six percent had undergone prior bypass surgery. Sixty- six percent were "protected" by i or more patent grafts to the left coronary system at the time of PTCA. Seven- ty percent underwent associated dilatation of other lesions, with a primary success rate of 92% for dilata- tion of the left main artery and other sites. Emergency bypass surgery was needed in 1.9%, and the proce- dure-related mortality was 3.9%. 33G

Upload: geoffrey-o-hartzler

Post on 13-Sep-2016

214 views

Category:

Documents


1 download

TRANSCRIPT

Page 1: “High-risk” percutaneous transluminal coronary angioplasty

"High-Risk" Percutaneous Transluminal Coronary Angioplasty

GEOFFREY O. HARTZLER, MD, BARRY D. RUTHERFORD, MD, DAVID R. McCONAHAY, MD, WARREN L. JOHNSON, MD,

and LEE V. GIORGI, MD

Of 6,500 percutaneous transluminal coronary angio- plasty procedures performed between June 1980 and June 1987, 3,501 (1,604 single lesion and 1,897 multiple lesion) were performed in "low-risk" patients with a procedure-related mortality of 0.2 to 0.3%. In comparison, several clinical variables were identified that increased procedural risk by up to 50-fold. These factors include left main dilatation (n = 103, mortality 3.9% ), left main equivalent di- latation (n = 77, mortality 2.6%), ejection fraction

< 4 0 % (n = 664, mortality 2.7%), age >70 years (n = 1,038, mortality 1.4%), dilatation of all 3 ves- sels (n = 305, mortality 1.3%), combined diagnos- tic catheterization and angioplasty for unstable angi- na (n = 193, mortality 1.5%), and percutaneous transluminal coronary angiopiasty for acute myocar- dial infarction (n = 446, mortality 8.5%). Important considerations in the selection and management of these high-risk patients are discussed.

(Am J Cardiol 1988;61:33G-37G)

~n experienced centers, percutaneous transluminal coronary angioplasty (PTCA) is now routinely per- formed in patients who had previously been consid- ered unsuitable for the procedure because of concerns about procedural success, increased procedural mor- bidity and mortality or unfavorable late outcome. This "high-risk" group has traditionally included patients with multiple vessel disease, multiple lesion dilata- tion, advanced age, prior coronary bypass surgery, poor left ventricular function, and left main disease requiring dilatation. 1

This report describes the results of angioplasty in patients with these characteristics and emphasizes im- portant procedural aspects.

Patients (Table I) From June 1980 through June 1987, 6,500 proce-

dures were performed at the Mid America Heart Insti- tute in Kansas City, Missouri. Of 13,805 stenoses at- tempted, primary success, defined as >_20% reduction in stenosis diameter and _<50% residual diameter nar- rowing was achieved in 94%.

Complications included transmural myocardial in- farction in 0.5% and urgent bypass surgery in 1.7%.

From Medical Plaza II-20, Kansas City, Missouri. Address for reprints: Geoffrey O. Hartzler, MD, Medical

Plaza II-20, 4320 Wornall Road, Kansas City, Missouri 6411.

With the exclusion of patients who presented with acute myocardial infarction, the procedural mortality was 0.7%. If patients >_70 years of age or with poor left ventricular function, prior bypass surgery and left main coronary disease are also excluded, 1,604 pa- tients who underwent single lesion PTCA had a pro- cedural mortality of 0.3%, and 1,897 patients who underwent multiple lesions PTCA had a procedural mortality of 0.2"/o (difference not significant].

Results in these "low-risk" groups provide a refer- ence standard for the subsequent discussion. The sub- sets described are not mutually exclusive.

Analysis of Percutaneous Transluminal Coronary Angioplasty (PTCA) and High-Risk Subsets

Lef t m a i n PTCA: One-hundred three procedures (1.6%) included elective dilatation of the left main cor- onary artery. The mean age of the patients in this group was 62 years, and 24% had poor left ventricular func- tion defined as an ejection fraction of _<40"/o. Seventy- six percent had undergone prior bypass surgery. Sixty- six percent were "protected" by i or more patent grafts to the left coronary system at the time of PTCA. Seven- ty percent underwent associated dilatation of other lesions, with a primary success rate of 92% for dilata- tion of the left main artery and other sites. Emergency bypass surgery was needed in 1.9%, and the proce- dure-related mortality was 3.9%.

33G

Page 2: “High-risk” percutaneous transluminal coronary angioplasty

34G A ~Ylv uSIUM: INH: , ,VtNI IONAL (..;ARuIuLuL~Y--198(

At mean follow-up of 16.7 months, 12~/, required late bypass surgery, 4~/~ had late myocardial infarction and 28~/~ had died. The late mortality for those patients with a protected left coronary system was 12.5~/, com- pared with a 56% mortality (p <0.01) in "unprotected" patients. Three-year survivorship in protected patients was 87% compared with 40c/, in unprotected patients (p <0.01).

Given the frequently associated presence of poor left ventricular function, advanced age, multiple pre- vious bypass operations and absolute or relative in- operability, it is difficult to evaluate the appropriate- ness or effectiveness of PTCA in this patient group in the absence of a randomized trial.

Left main equivalent PTCA: "Left main equivalen- cy" can be defined as >_70~/~ stenosis in both the left anterior descending artery before the first septal perforator and in the circumflex artery before all branches, in the absence of a significant intermediate branch. Of 77 patients in this subset, primary success was achieved in 957(. Myocardial infarction occurred in 1.3c/c, urgent bypass surgery in 6.5% and procedure- related mortality in 2.67(. This compares favorably with the 3.1% procedural mortality in patients with left main equivalent disease undergoing bypass surgery as part of the Coronary Artery Surgery Study recorded by Chaitman et ah a Three-year survivorship for these 77

TABLE I Risk of Percutaneous Transluminal Coronary Angioplasty (PTCA) According to Subgroups*

Success MI EMCABG Death Risk No. (%) (%) (%) (%) Ratio ~

Total 6,500 94 0.5 1.7 0.7 - - Single lesion 2,888 93 0.4 2.1 0.6 - - Multiple lesion 3,612 95 0.6 1.4 0.8 - - Prior CABG 1,225 94 0.6 1.4 0.9 - -

"Low-r isk" Single lesion 1,604 88 0.6 2.4 0.3 - - Multiple lesion 1,897 96 0.1 1.5 0.2 - -

"High-risk" Left main 103 92 0.9 1.9 3.9 5.9 Left main equiv* 77 95 1.3 6.5 2.6 3.8 EF --<40% 664 93 0.7 2.0 2.7 5.9 Age >70 (yr) 1,038 94 0.8 1.3 1.4 2.6 Atl 3 vessels§ 305 97 0.6 1.0 1.3 1.9 CATH/PTCA for UA I~ 193 96 1.5 2.0 1.5 2.2 Acute infarction ̀ ] 446 93 - - 2.9 8.5 11.2

EF > 3 0 % 383 - - - - - - 3.7 5.1 EF < 3 0 % 63 - - - - - - 38 52.9 EF > 3 0 % Age <70 (yr) 325 - - - - - - 1.5 2.1

• Infarct interventions are excluded from "high-risk" subsets except "acute infarction."

r Approximate risk relative to all other patients undergoing angioplasty. ~t From 5,000 procedures. § From 5,568 procedures. II From 3,197 procedures. ¶ From 5,000 procedures. Risk ratio is risk of infarct intervention relative to

all elective procedures.

CABG = coronary artery bypass grafting; CATH = catheterization; EF = ejection fraction; EMCABG = emergency coronary artery bypass surgery; equiv = equivalent; MI = myocardial infarction; UA = unstable angina.

patients was 88c/f, again comparing favorably with Chaitman~s report of 91% for patients in this subgroup undergoing bypass surgery.

PTCA in patients with poor left ventricular func- tion: Excluding those patients presenting with acute myocardial infarction, 664 patients underwent elec- tive PTCA in the setting of ejection fraction <_407,. Primary success [by lesion) was 93%, with nonfatal infarction of 0.7G/f and urgent bypass surgery in 2.07, . Procedural mortality was increased at 2.7%, but com- pares favorably with published surgical data for simi- lar patients. 3 The late results in patients with poor left ventricular function undergoing PTCA have not been characterized at the present time, and analysis is com- plicated by the presence of other high-risk variables (multiple prior bypass surgeries, advanced age and ventricular arrhythmia} in the poor left ventricular function subgroup.

PTCA in elderly patients: Angioplasty was per- formed in 1,038 patients >_70 years of age. Sixty per- cent underwent multiple lesion dilatation procedures. The primary success was 94%, with nonfatal myocar- dial infarction of 0.87, and urgent bypass surgery in 1.3~/, ,. Procedure-related mortality was 1.4%.

In a previous report, we characterized the late re- sults of multilesion PTCA in 100 patients >_70 years of age. 4 For patients with both 1- and 2-vessel disease, 3- year survivorship was 94'7,, while patients with 3-ves- sel disease had a much worse 3-year survivorship of 56% (p <o.003).

We have analyzed the results of PTCA in patients with extremely advanced age (80 to 92 years) separate- ly. 5 Of 75 patients in this subgroup, 60~/, had class IV angina and 20~/, had poor left ventricular function. Seventy percent of patients had multiple vessel dis- ease and 59% underwent multiple lesion PTCA. The primary success rate was 899~, with procedure-related myocardial infarction of 1.2c/(, no emergency bypass surgery, and procedure-related mortality of 3.57,. At mean follow-up of 20.1 months, the occurrence of late infarction was 1.4~/,, crossover to elective bypass sur- gery was 13% and total mortality was 247, . Using actu- arial techniques, survivorship was 77°/, at 1 year and also at 2 years. In these elderly patients, PTCA was accomplished with significantly less risk than the 7.9°/, mortality reported by Kennedy et al 6 for aged patients in the Coronary Artery Surgery Study registry, and 11'Y~ operative mortality reported by Naunheim et al 7 for patients >80 years old.

Multiple vessel and multiple lesion PTCA: A total of 3,612 patients underwent dilatation of 2 or more stenoses during a single angioplasty procedure, which involved multiple vessels in more than 75c/, of cases. Procedural success (by lesion attempted) was 95~/, with procedure-related myocardial infarction of 0.6~/~ and emergency bypass surgery in 1.47,. Excluding acute infarct interventions, procedural mortality for patients undergoing multiple lesion PTCA was 0.8'7,.

We previously described the late results of multiple lesion coronary angioplasty in 500 consecutive patients followed for 1.2 to 4.4 years (mean follow-up of 2.3

Page 3: “High-risk” percutaneous transluminal coronary angioplasty

May 9, 1988 THE AMERICAN JOURNAL OF CARDIOLOGY Volume 61 35G

years}. 8 Life-table analysis showed an overall 90% sur- vivorship at 4 years, with 97% survivorship in patients without 1 or more of the high-risk factors described. Late bypass surgery was performed in 16% of patients. Although 23% of patients required repeat PTCA pro- cedures, more than one-fourth of those procedures were performed for new stenoses developing in the follow-up period rather than for restenosis.

In view of these data and the low procedural mor- tality reported previously (0.2%] for isolated multiple lesion dilatations in the absence of associated high risk factors, we believe that both the acute and late results of multiple lesion angioplasty are favorable. Random- ized trials are currently underway to compare multiple lesion PTCA with multiple vessel bypass surgery in selected patient subgroups.

PTCA of the left coronary system in the setting of chronic right coronary occlusion: Limited data are available concerning this specific patient subset. We compared 65 consecutive patients who had dilatation within the left coronary system in the setting of chronic right coronary occlusion, with 105 consecutive patients having dilatation within the left coronary system in the absence of right coronary disease. There was no signif- icant difference between primary success or proce- dure-related infarction, urgent bypass surgery or mor- tality between groups.

PTCA within all three major coronary arteries as a single procedure: Three hundred five patients un- derwent dilatation in each of the 3 major epicardial coronary arteries, with an average of 4.8 stenoses at- tempted per patient at a single procedure. 9 The pri- mary success {per lesion) was 97%, with emergency bypass surgery in 1.0% and procedure-related mortali- ty in 1.3%.

Diagnostic angiography and simultaneous PTCA for unstable angina: In a subset of 193 consecutive patients presenting with unstable angina undergoing 200 procedures, and in whom diagnostic coronary angiography and PTCA were performed as a single procedure, the primary success rate was 96% .lo Proce- dure-related infarction occurred in 1.5%, urgent by- pass surgery in 2% and procedural mortality in 1.5%. At a mean follow-up of 20 months, late infarction had occurred in 2%, late bypass surgery in 10% and late cardiac mortality in 4%. Actuarial survivorship at 3 years was 91%.

PTCA for acute myocardial infarction: Direct cor- onary angioplasty in the absence of previous thrombo- lytic therapy was performed in 446 patients presenting with acute myocardial infarction. Primary success, de- fined as the ability to reopen the infarct artery to less than 50% residual narrowing, was 93% with a total in- hospital mortality of 8.5%. We have previously de- scribed correlates of acute reocclusion, 11 improvement in regional wall motion 12 and in-hospital mortality. 13 The 73% of patients who were <70 years of age and had a left ventricular ejection fraction >30%, had a total procedural and in-hospital mortality of 1.5%. Pa- tients with an ejection fraction of <30% had a proce- dural and in-hospital mortality of 38%. There are no

current data that allow a valid comparison between di- rect angioplasty and surgical or thrombolytic therapy.

Discussion In addition to the subsets previously described, it is

clear that several other patient groups may have either reduced angioplasty success rates, increased risk or a less favorable late course, or a combination of all 3. This could include patients with extreme coronary tor- tuosity, small vessels, diffuse disease, total occlusions, various associated medical conditions {e.g., diabetes or renal failure}, advanced age with 3-vessel disease or poor left ventricular function, and dilatation of the only remaining patent vessel supplying the myocardi- um. These patients have yet to be well characterized in published reports on angioplasty, and are difficult to compare with surgical reports in the absence of ran- domized trials, but constitute a growing segment of current angioplasty performance. To obtain satisfacto- ry results in this difficult patient population, special attention must be paid to patient selection and proce- dure performance.

Management strategy: The management of pa- tients with increased procedural risk must be individ- ualized. In these cases, close collaboration between the clinician, invasive cardiologist and surgeon is use- ful in deciding on the optimal therapeutic recommen- dation for providing the best symptomatic relief with the lowest procedural risk. Multiple previous bypass surgeries generally favor angioplasty, particularly if some grafts remain patent and if the internal mamma- ry arteries have already been used, or if no useable veins remain in the lower extremities. Although cer- tain patterns of coronary anatomy may be associated with decreased procedural success, PTCA may still be appropriate, particularly if complications of attempt- ing dilatation of such an artery might be medically managed without need for urgent operation. In some cases, the procedural goal is frequently palliation rath- er than total revascularization. For example, bypass surgery may provide more complete revascularization in an aged patient with a chronically occluded right coronary artery, but angioplasty directed toward easily dilatable lesions in the left coronary system may be preferable because it affords acceptable clinical relief at lesser procedural risk. When a patient is considered inoperable for any reason, angioplasty may still be warranted if the coronary anatomy is appropriate, and anticipated clinical benefit is substantial, despite the low likelihood or impossibility of surgical salvage should a life-threatening complication occur.

Intraaortic balloon support: The prophylactic in- sertion of an intraaortic balloon has proved valuable in specific patient subsets, including those with moderate to severe depression of left ventricular function. We also favor its use during PTCA of the only remaining source of myocardial blood flow (a single artery or graft open to the heart), during PTCA of an unprotect- ed left main coronary stenosis or a protected left main stenosis associated with moderately depressed left ventricular function, and PTCA in the setting of acute

Page 4: “High-risk” percutaneous transluminal coronary angioplasty

36G A SYMPOSIUM: INTERVENTIONAL CARDIOLOGY--1987

anterior infarction with high left ventricular end-dia- stolic pressure or extensive regional wall motion ab- normalities. In other patients, an intraaortic balloon should be considered if hypotension develops which is not rapidly corrected by fluid replacement and modest doses of pressors, since rapid correction of hypoten- sion is helpful in preventing acute reocclusion of freshly dilated lesions.

PTCA of the left main artery: The first and most important consideration is that angioplasty of the left main artery sheuld be avoided if the patient is an oper- ative candidate. Although no randomized trial com- paring PTCA with bypass surgery has been performed, the hazards of left main dilatation or subsequent re- stenosis, or both, are apparent to all invasive cardiolo- gists. However, patients with left main stenoses who are "relatively" inoperable can justifiably be helped only through coronary angioplasty.

After placement of an intraaortic balloon pump, we generally approach coexistent right coronary stenoses or graft stenoses first, attempting to maximize left ven- tricular perfusion and facilitate collateral flow to the left coronary system to lower the intrinsic risk of the left main coronary dilatation itself. Although pa- tients occasionally tolerate 30-second balloon infla- tions within the left main artery, and a patient will rarely tolerate a 60-second or longer balloon inflation, most demonstrate narrowing of the pulse pressure and decline in systemic blood pressure within 5 to 10 sec- onds of left main occlusion. Consequently, we perform shorter balloon inflations, while closely observing changes in systemic blood pressure and heart rate as further clues to shorten the duration of balloon infla- tion. Meticulous attention must be directed toward po- sitioning of the guide catheter in such a way as to minimize additional left main obstruction or deep in- sertion into the main artery after balloon inflation.

In our experience, better angiographic patency has been achieved with an incremental approach, initially undersizing the balloon followed by step-wise in- crease in balloon dimension and inflation pressures. However, many patients cannot tolerate the prolonged manipulation required for this incremental approach, prompting the use of a larger balloon and high infla- tion pressures at the outset. A unique failure mode during PTCA of the left main artery appears to result from intrinsic elasticity of this vascular segment. On occasion, a stenosis of the left main artery will resume its pre-PTCA appearance on balloon deflation despite use of the proper-sized or even an oversized balloon. On other occasions, cautious overexpansion has lead to marked angiographic improvement.

Poor left ventricular function: We initially attempt to optimize left ventricular function through the use of diuretics, vasodilators and inotropes, as appropriate. When possible, ~ blockers should be withdrawn at least 24 hours before the procedure. Their presence not only compromises the patient's ability to respond to inotropic agents when needed during the proce- dure, but also reduces the patient's ability to tolerate a contrast load. Volume expanders such as dextran are not used. For severe impairment with ejection fraction

of less than 30%, we favor the placement of a prophy- lactic intraaortic balloon pump. The management of patients with poor left ventricular function has been facilitated through the introduction of low osmolality contrast agents that produce less depression of myo- cardial function and less bradyarrhythmia than tradi- tional contrast agents.

The operator should pay careful attention to the patient's hemodynamic status and to any evidence of pulmonary congestion developing as the procedure progresses. If the pulmonary artery pressure is not monitored directly, fluoroscopy of the lungs may re- veal progressive upper lobe distribution of blood flow as well as prominence of the minor fissure in time for diuretics, afterload reduction and intraaortic balloon pumping to prevent the development of frank pulmo- nary edema. If the patient's condition is hemodynami- cally precarious, dilatation should be limited to truly significant and critical stenoses within major vessels, as opposed to lesser obstructions and those within smaller branches. In some but not all patients with poor left ventricular function, the optimal strategy in- cludes not attempting to dilate chronically totally oc- cluded arteries, because these lesions require much more time to achieve a satisfactory result and require additional contrast administration that may further de- crease patient tolerance.

Axioms: If any "axioms" exist in relation to high- risk PTCA, they might include the following: {1) It is imperative to discuss fully the patient's circumstance, options and risks with the patient and family members. (2) It is always helpful to obtain the opinion of other cardiologists and cardiovascular surgeons. (3) If pro- ceeding with PTCA, one should consider a higher lev- el of surgical standby for those patients who may still have a surgical option for survival should a major angi- oplasty complication occur. (4) PTCA in high-risk sub- groups should be limited to the most experienced and capable operators. (5) High-risk PTCA should not be confused with either technically complex or multiple vessel PTCA. (6) Assuming there is an experienced and competent operator, the risk of PTCA is deter- mined largely by associated clinical factors, such as poor left ventricular function, advanced age, acute myocardial infarction and left main or left main equiv- alent disease.

References 1. Wa]sh RA, O'Rourke RA. Percutaneous t raosluminal coronary angioplusty: how useful for whom? Ann lnt Mud 1979;91:778-779. 2. Chaitman BR, Davis KB, Kaiser GL, Mudd G. Wiens RD, Ng GS, Passamani ER, KiIlip T, and participating CASS hospitals. The role of coronary bypass surgery for "left main equivalent" coronary disease: the Coronary Artery Surgery Study Registry. Circulation 1986;74:suppl III:I11-17-III-25. 3. Alderman EL, Fisher LD, Litwin P, Kaiser G, Myers WO, Maynard C. Levine F, Schloss M. Results of coronary artery surgery in patients with poor left ventricular function {CASSI. Circulation 1983;68:785-795. 4. Hartzler GO, Rutherford BD, McConahay DR, Johnson WL. Ligon B, Cal- kins MM. Late results of multiple lesion coronary angioplasty in the aged population {abstr}. ]ACC 1986:7:21A. 5. Good TG, Calkins M. Ligon R, McCallister BD, Hartzler GO. PTCA in the ultra-elderly [abstr). Circulation 1987:76:suppl IV:IV-464. 6. Kennedy JW, Kaiser GC, Fisher LD, Fritz JK, Myers W, Mudd JG, Ryan TJ. Clinical and angiographic predictors of operative mortality from the collabo- rative study in coronary artery surgery (CASS). Circulation 1981;63:793-802. 7. Naunheim KS, Kern MJ. McBride LR, Pennington DG, Barner HB, Kanter KR, Fiore AC, Willman VL, Kaiser GC. Coronary artery bypass surgery in

Page 5: “High-risk” percutaneous transluminal coronary angioplasty

May 9, 1. ,8 i In= AM=, ~AN dW= qAL (Jr (.;AHU, J L ( J ~ ' Volume o l ~

patients aged 80 years or older. Am [ Cordial 1987;59:804-807. 8. Hartzler GO, Rutherford BD, McConahay DR, Johnson WL, Ligon RW, Calkins MM. "Long-term" clinical results of multiple lesion coronary angio- plosty in 500 consecutive patients (abstr). Circulation 1985;72:suppl III: III-139. 9. Giorgi LV, Hartzler GO, Rutherford BD, McConahay DR, Johnson WL. Single-procedure PTCA for triple-vessel coronary disease: results and long- term follow-up (abstr]. Circulation 1987;76:suppl IV:IV-399. 10. Gura GM, Rutherford BD, Hartzler GO, McConahay DR, Johnson WL, Giorgi LV, Calkins M. Simultaneous coronary angiography and angioplasty in unstable angina (abstr}. Circulation 1987;76:suppl IV:IV-451.

11. Samari RD, Rutherford BD. Ligon RW. Giorgi LV, Osborn IS. McConahay DR. Hartzler GO. ]ohnson WL. McCallister BD. PTCA in acute myocardial infarction: a multi-variate analysis of predictors of early reocclusion [abstr). Circulation 1986;74:suppl II:II-95. 12. Rutherford BD, Samari RD, Ligon RW, McConahay DR, Johnson WL, Hartzler GO. Multivariate analysis of factors predicting improvement in regional wall motion following direct balloon angioplasty in acute myocardial infarction (abstr). /ACC 1987;9:23A. 13. Rutherford BD, Hartzler GO, McConahay DR, ]ohnson WL. Direct bal- loon angioplasty in acute myocardial infarction: without prior use of strepto- kinase. [ACC 1986;7:149-A.