Clinical profile and underdiagnosis of pulmonary hypertension in US veteran patients

Abstract

Background: Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations.

Methods and results: The echocardiography registries from 2 major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure ≥60 mm Hg detected echocardiographically. From a total of 10 471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean, 77 years; mean pulmonary artery systolic pressure, 69.4±10.5 mm Hg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0-4817 days) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. PH was present without substantial left heart remodeling: the mean left ventricular ejection fraction was 0.50±0.16, left ventricular end-diastolic dimension was 5.0±0.9 cm, and left atrial dimension was 4.4±0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5±11.4 mm Hg, pulmonary capillary wedge pressure of 22.6±8.9 mm Hg, and pulmonary vascular resistance of 4.6±2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion scan for thromboembolic causes of PH.

Conclusions: in an at-risk patient population, PH is underdiagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.

Keywords: diagnosis; epidemiology; pulmonary hypertension.

Figure 1. Methods for identifying the study population

Results from transthoracic echocardiograms performed for any clinical indication at two Veterans Affairs (VA) medical centers were reviewed for the presence of pulmonary hypertension (PH), defined here as an estimated PASP ≥40 mmHg (calculated by the sum of the trantricuspid valve gradient plus estimated right atrial pressure). Patients likely to meet conventional criteria for severe PH were then selected for further analysis based on the presence of an estimated PASP ≥60 mmHg. PVAMC, Providence Veterans Affairs Medical Center; VABHS, Veterans Affairs Boston Healthcare System.

Figure 2. The distribution of tests used to diagnose pulmonary hypertension (PH) etiology and severity

The electronic medical record for each patient with echocardiographically assessed moderate or severe PH (N=340) was analyzed to identify patients undergoing specific test(s) that are important for establishing PH disease etiology as well as disease severity. PFT, pulmonary function test (spirometry only); DLCO, lung diffusion capacity to carbon monoxide; RHC, right heart catheterization; CT-A, thoracic computed tomographic angiography; V/Q, ventilation/perfusion.

Figure 3. Cardiovascular or pulmonary co-morbidites reported for the patient cohort

Primary cardiovascular or pulmonary disease accounted for nine of the ten most common comorbidites reported for the patient cohort, with osteoarthritis as the single non-cardiopulmonary condition (data not shown). COPD, chronic obstructive pulmonary disease.

Figure 4. Selected patient medications recorded at the time of data analysis

ACE, angiotensin converting enzyme; PDE-V, phosphodiesterase type-V; HMG-CoA reductase inhibitor (‘statin’).

Figure 5. Distribution of diastolic filling patterns for Veteran patients with severe pulmonary hypertension as assessed by tissue Doppler echocardiography (N=340)