ABSTRACTS

CLINIC AND HEMODYNAMIC EWALUA'I'ICRJ OF 118 PATIFWIS UNDER CXlXGMITRALFLEXIBJXRIK~PI..aSTy. Jo& L. PaMlr, M.D.; Alvaro Figueroa,M.D.; Albert0 O&o- teco, M.D.; Jos6 L. Ubago, PI.D. and Carlos G. Wdn, M.D. Ph.D. Centro NEdico ?Gacional Valdecilla. Universidad de Santander. Santar&r. Spain.

Reconstruction of all patl-ologicalmitral valves -unless heavily calcified- is almys attmpted at - Institution. An essential step in this conservative prccedure is a se- lective annulus reduction using - totally Flexible Ring which does not interfere with the physiological annular movements. 501 mitral patients were operated between January 1975 atrl June 1977. In only 45% of them a repla- cement was required. 118 @ients had a FlexibleRing in- serted in the mitral position, 30 of them urderwen t tri- cuspidard 35 aortic associated surgery. In thegrcupof 88 patients without tricuspid disease (27 with concani- tant aortic surgery) no bxpital and only one late death (carcinanatosis) cccurred. In thegroupwithsinmltanecus tricuspid annuloplasty there were 2 early ti one late deaths. Follow-up is 3 to 33 months. 3 non fatal thranko- enbolic accidents have been detected. All 114 survivors moved to Class I or II except 4 patients. 40 cases have beenrecatheterized : the basalmean transnitralgradient dropped fran 16.7 (+ 7.8) to 9.9 (+ 4.1) ax-d after volume load fran 21.9 (+ 8.2) to 13.7 (+ 5.9). Angicgraphically 10 patients had a significant regurgitation and 7 had to be reoperated without mortality, performing a valve repla caent (3) or ring resuture (4). In conclusion, it is felt that this technioue is a safe, stable and therefare valuable adjunct to the conservative surgery of the mi- tral valve.

PULSATILE FLOW DYNAMICS DURING STRESS IN PATIENTS WITH AORTIC PORCINE HETEROGRAFTS AFTER 1 YEAR. Wilmer W. Nichols, PM, Leonard G. Christie, MD, Carl J. Pepine, MD, FACC, R. Charles Curry, MD, and C. Richard Conti, MD, FACC, U. of Florida, Gainesville, Fla.

Aortic root blood flow characteristics were examined during isoproterenol stress in 7 patients with ejection fractions (EF) >50% 12 months after aortic valve replace- ment with porcine heterografts and compared to 7 pts. with EF 250% and normal aortic valves. Pulsatile aortic root blood flow velocity waveforms were measured with an electromagnetic catheter-tip velocity transducer. Mea- surements of stroke volume (SV). peak blood flow velocity (PV) and acceleration (MA). ejection time (ET) and mean aortic pressure (AoP) were made under control resting conditions and during the intravenous injection of 3 pgm isoproterenol. Only two pts. had resting valvar gradi- ents (6. 17 mm Hg.) while none had insufficiency by pul- _ _. satile waveform analysis or angiography. RESULTS: Normal Porcine P

HR(bpm) 99+5.3 94+7,0 NS SV(cC) 9277.3 95710.8 NS PV(cm/sec

1 88719 113T18 NS

MA(cm/sec ) 21447408 2832+313 NS ET(msec) 234T11.2 22579.8 NS AoP(dg) 783.9 91z8.5 NS

CONCLUSIONS: During stress, as well as under resting conditions, aortic root velocity waveforms in pts. with porcine valves after 1 year were not significantly dif- ferent from those with normal valves. However, pts. with porcine heterografts tended to have higher PV and MA than normals possibly related to the effects of unloading a hypertrophic ventricle. The normal flow dynamics of the aortic porcine heterograft may contribute to the low in- cidence of thromboemboli and to the longevity of the valve.

PLASMA VASOPRESSIN LEVELS AND URINARY ELECT- ROLYTE CONTENT DURING CARDIOPULMONARY BYPASS. Daniel M. Philbin, M.D., F.A.C.C.; and Cecil H. Coggins, M.D.; Massachusetts General Hospital, Boston, Mass.

We have previously reported high levels of plasma vasopressin (VP) during cardiopulmonary bypass (CPB) with light halothane anesthesia. This study was undertaken to determine the effect of deeper anesthesia on VP and urinary electrolytes in 14 pts. who were studied before, during and immediately after CPB. In Group I (halothane anesthesia) VP was elevated above control during surgery (82.4*23 pg/ml-pc0.01) and bypass (172.4+23 pg/ml-p<O.OOl) and grad- ually declined following CPB (89.3+16 pglml- pcO.01). Urine Na+ rose during CPB (127r4 meq/L -p<O.Ol) and urine K+ declined (30+8 meq/L-p c0.01). In Group II (morphine anesthesia Zmgm/kg) VP did not rise until CPB (58.3*16 pg/ml-pc0.01) again falling after CPB (21i5 pg/ml-p<O.OS). During CPB urine Na+ increased (98514 meq/L-pc0.01) and urine K+ declined (57t12 meq/L-N.S.). The rise in VP was greater in Group I than Group II (p<O.Ol)as was the rise in urine Na+ (~~0.05) and the fall in K+ (~~0.01) during CPB. These data suggest that the VP rise is a stress response which can be attenuated by deeper morphine anesthesia. It also suggests that the Na+ diuresis during CPB is VP related.

COMPARISON OF CARDIAC INDEX IN CHILDREN FOLLOWING NORMO- THERMIC AND HYPOTHERMIC REPAIR OF TETFALOGY OF FALLOT AND VENTRICULAR SEPTAL DEFECT Peter Lang, MD: Carl W. Chipman, RN; Roberta G. Williams, MD; William I. Norwood, MD; Aldo R. Castaneda, MD Children's Hospital Medical Center, Boston, Massachusetts

Cardiac index(CI measured by the thermodilution tech- nique using a 2 Fr thermistor within 2 hours of intracar- diac repair in 25 patients with tetralogy of Fallot(TOF) and 16 after transatrial closure of ventricular septal defect(VSD). Deep hypothermic circulatory arrest(DH employed in 18 patients(TOF 10, VSD 8); the remainder were repaired using normothermic cardiopulmonary bypass (NCPB). There were no early or late deaths. None had evi- dence of a residual intracardiac shunt or significant right ventricular outflow obstruction. Significant dif- ferences in CI were found between patients undergoing VSD (mean 3.58f0.88)and TOF(mean 2.51*0.75)repair with p < 0.001. Significant differences in CI were measured between the DH and NCPB patients in each category. In the VSD group mean CI was 4.14f0.61 in NCPB and 3.03f0.76 in DH patients(p(0.01). In TOF values were 2.71f0.85 and 2.21* 0.46 in NCPB and DH patients(p<O.l). Significant differ- ences in CI were also noted when comparing all NCPB patientsfmean 3.21*1.03)with all DH patientscmean 2.57* 0.73)with peO.025. Although we have no explanation for the differences in CI between the NCPB end DH groups the de- creased CI in TOF relative to VSD patients may reflect added disability caused by right ventriculotomy and right ventricular outflow patches..

422 February 1978 The American Journal of CARDIOLOGY Volume 41