Potential Role of the Ventilation and Perfusion (V̄/Q)Lung Scan in the Diagnosis of Acute Chest Syndrome

in Adults With Sickle Cell Disease

Navleen Kaur, Bharat Motwani, Devaki Sivasubramaniam, Lori Feldman, Sandra Allen,Richard Ferguson, Gail Shiomoto, David Ansell, Maxwell Westerman, and Lawrence Feldman*

Department of Medicine, Finch University of Health Sciences̄/The Chicago Medical School at Mount Sinai

Hospital Medical Center, Chicago, Illinois

The current criteria for diagnosing ACS are chest pain and presence of a new infiltrate on

the chest radiograph (CXR). This study was designed to evaluate the role of ventilation

and perfusion (V̄/Q) scan to assist in the early diagnosis of ACS. An abnormal V̄/Q scan

was associated with a diagnosis of ACS that reached a statistical significance (P < 0.038).

The sensitivity and specificity were found to be 60% and 100%, respectively. We con-

clude that V̄/Q scan may play a role in the early diagnosis of ACS. Am. J. Hematol.

77:407–409, 2004. ª 2004 Wiley-Liss, Inc.

Key words: sickle cell disease; acute chest syndrome; ventilation and perfusion; lung

scan; V̄/Q scan

INTRODUCTION

Acute chest syndrome (ACS) is the leading cause ofdeath among patients with sickle cell disease (SCD)[1–3]. Significant reduction in morbidity and mortal-ity can be achieved with early diagnosis and treatment[3]. The current criterion for diagnosing ACS is chestpain and the appearance of a new infiltrate on thechest radiograph (CXR) [3,4]. The CXR may notshow an infiltrate for several days or not at all, thusdelaying the diagnosis [5,6]. It was recently suggestedthat ventilation–perfusion scan (V/Q) could be usefulin the diagnosis of ACS [5,7,8].To investigate the utility of this test, we performed

a review of all SCD patients in our database who hada V/Q scan for suspected ACS. Our data support thehypothesis that V/Q scan may play a role in the earlydiagnosis of ACS.

PATIENTS AND METHODS

Patients with SCD and patients who had a V/Qscan ordered were identified via queries of the SinaiHealth System Data Warehouse (SHSDW) from theyears 1996 to 2001. The SHSDW is a Microsoft SQLserver database containing all demographic, visit

history, orders, and clinical data for patients seen atSinai Health System. Queries were performed againstthe laboratory data in the SHSDW to identify thosepatients who had positive sickle cell tests (1,552patients) and against the billing data to identifythose billing codes indicative of a V/Q scan havingbeen ordered (1,801 orders). These results were joinedto yield the set of patients who were positive for asickle cell disorder and who had a V/Q scan ordered(21 patients).Hemoglobin (Hb) electrophoresis for all patients

was verified. Nine patients with Hb other than SSand two patients where V/Q scan was ordered butnot done were eliminated from further analysis. Thus,a total of 10 patients were included in this study.Their signs and symptoms, laboratory results, CXR,and V/Q scan reports were recorded.

*Correspondence to: Lawrence Feldman, M.D., Hematology/Oncology Unit, Mount Sinai Hospital Medical Center, CaliforniaAvenue at 15th Street, Chicago, IL 60608. E-mail: fell@sinai.org

Received for publication 28 April 2004; Accepted 26 May 2004

Published online inWiley InterScience (www.interscience.wiley.com).DOI: 10.1002/ajh.20179

American Journal of Hematology 77:407–409 (2004)

ª 2004 Wiley-Liss, Inc.

RESULTS

A total of 10 patients from our sickle cell database,who met the inclusion criteria, were included in thisretrospective study (see Table I). There were sixwomen and four men, their ages ranging between 18and 47 years (average, 30.9 years). One patient wasnoted to have hemoglobin type SC, and the nineothers had SS type. Three of them complained onlyof chest pain, whereas the rest had one or more addi-tional complaints. Laboratory data showed a hemo-globin level median of 8.35 g/dL, reticulocyte fraction(%) median of 14.2, WBC count median of 19.05/mm3, and the platelet count was between 121 � 106/mL and 147 � 106/mL. All 10 patients had CXR andV/Q scan done on admission. Seven patients had asecond CXR done on day 3. In three cases, the initialCXR showed an infiltrate; in one case, a follow-upCXR done on day 3 showed left lower lobe infiltrate.Correlations between V/Q scans and CXR findingsare presented in Table I.The association between the diagnosis of ACS and a

perfusion defect on the V/Q scan was found to be statis-tically significant (P<0.038). The sensitivity of the V/Qscan was found to be 60% with a specificity of 100%.

DISCUSSION

Early diagnosis of ACS can reduce mortality andmorbidity [3]. The need to make an early diagnosishas prompted investigators to evaluate the role ofother diagnostic modalities [9,10]. In our study, thesensitivity and specificity of V/Q scan were found tobe 60% and 100%. Therefore, in patients with sus-pected ACS and a negative CXR, a positive V/Q scancould provide an opportunity for early diagnosis andtreatment.

An abnormal perfusion scan may persist formonths; therefore it was assured that all the scanswere performed within the first week of admission.It is possible that a V/Q scan can demonstratechanges that are chronic and not associated with theacute event, but the strong statistical significance ofour data suggests that this was not an importantconfounding variable.An important factor that needs to be investigated

further is the interpretation of the V/Q scan as thecurrent interpretation has been used for pulmonaryembolism (PE) and not ACS. ACS usually presentswith perfusion defects [7], and thus an intermediateprobability could be as strong as a high probabilityfor PE. In our study, all patients with intermediate-probability V/Q scans were diagnosed with ACS. Oneof the main limitations to our study was that it was asingle-institution retrospective study. Additional stud-ies on a larger level are warranted.

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TABLE I. Clinical Descriptions of Patients on Admission*

Patient Hb Hb level Reticulocyte WBC count Platelet count

CXR

no. Age/sex type Symptom (g/dL) count (%) (/mm3) (�106/mL) Day 1 Day 3 V/Q ACS

P1 21/F SC CP 11.6 3.9 22 328 NI ND LP �P2 39/M SS CP+F 6.9 21.4 20 424 NI NI LP �P3 29/F SS CP 9.3 16.8 13 350 NI NI LP �P4 44/F SS CP+TP 7.5 25 18.1 342 NI ND LP �P5 47/F SS CP+F+TP 6.9 24.2 17.1 333 RLL INF ND IP +

P6 18/F SS CP+TP+WZ 8.4 16.2 20.2 147 LLL INF NI LP +

P7 26/M SS CP+WZ 8.3 11 14.2 343 NI NI IP +

P8 20/M SS CP+F+WZ 8.7 12.2 35.1 1210 NI LLL INF LP +

P9 24/M SS CP+F 6.1 11 27 264 RLL+LLL RLL+LLL IP +

P10 41/F SS CP 8.8 5.7 16 300 NI NI LP �

*Abbreviations: ACS, acute chest syndrome; CP, chest pain; F, fever; TP, tachypnea; WZ, wheezing; NI, no infiltrate; ND, no subsequent CXR

done; LP, low probability; IP, intermediate probability; RLL, right lower lobe; LLL, left lower lobe; INF, infiltrate; +, positive; �, negative.

408 Brief Report: Kaur et al.

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