Chest
Volume 93, Issue 6, June 1988, Pages 1180-1185
Journal home page for Chest

Perfusion Scan Findings Understate the Severity of Angiographic and Hemodynamic Compromise in Chronic Thromboembolic Pulmonary Hypertension

https://doi.org/10.1378/chest.93.6.1180Get rights and content

Major vessel chronic thromboembolic pulmonary hypertension is potentially remediable by thromboendarterectomy. The diagnosis often has been delayed because a lung perfusion scan demonstrated modest defects thought to be incompatible with severe vascular obstruction. To define the relationships between perfusion scan abnormalities, angiographic findings, and hemodynamic data, we analyzed 25 consecutive patients with chronic major vessel thromboembolic pulmonary hypertension who subsequently underwent thromboendarterectomy. We found that the perfusion lung scan consistently caused us to underestimate the severity of pulmonary arterial obstruction as defined by pulmonary angiography. Furthermore, there was no significant correlation between the severity of hemodynamic compromise and the extent of obstruction defined by perfusion scan or angiogram. These findings suggest that, when pulmonary hypertension is known or suspected, the diagnosis of correctable, chronic major vessel obstruction should be pursued by angiography and hemodynamic assessment even though the perfusion scan may demonstrate only two segmental defects.

Section snippets

METHODS

The medical records, ventilation and perfusion scans, and angiograms of 25 consecutive patients with chronic TEPH, whose scans and angiograms were available, were reviewed. All patients had chronic large vessel TEPH diagnosed by right heart catheterization and pulmonary angiography; all subsequently underwent pulmonary artery thromboendarterectomy at the University of California, San Diego (UCSD) Medical Center between March 1984 and June 1986.

Right heart catheterization was performed

RESULTS

The study included 18 men and 7 women with a mean age of 44 years (range, 19 to 73 years). Mean PA pressure for the group was 45 mm Hg (range, 30 to 65 mm Hg). Mean pulmonary vascular resistance (PVR) for the group was 797 dynes•s•cm−5 (range, 311 to 1900 dynes•s•cm−5). Hemodynamic, angiographic, and perfusion scanning data are presented in Table 1.

The perfusion scans revealed two or more segmental-sized defects in all cases. In all, ventilation scans were normal (ie, ventilation/perfusion

DISCUSSION

The perfusion lung scan, the pulmonary angiogram, and direct hemodynamic measurement during right heart catheterization each provides invaluable information in the assessment of patients with known or suspected pulmonary hypertension. However, the data provided by each approach are quite distinct, and assumptions that one technique will reflect findings revealed by the others should be made cautiously, if at all. In chronic major vessel thromboembolic pulmonary hypertension, our analysis

Cited by (0)

Supported in part by NHLBI Pulmonary Training Grant (HL 07022-11), UCSD SCOR Grant (23584-09), and NIH Grant (RR-00827) to the UCSD General Clinical Research Center.

Manuscript received September 8; revision accepted December 1.

View full text