Survival and restoration of pulmonary perfusion in a long-term follow-up of patients after acute pulmonary embolism.

We followed prospectively 834 consecutive patients (70% inpatients), evaluated for suspected pulmonary embolism, for a median time of 2.1 years (range, 0-4.8 yr), and compared the survival rates in patients with proven pulmonary embolism (n=320) with those without (n=514). In multivariate analysis, we modeled the probability of surviving in patients with pulmonary embolism as a function of the extent of pulmonary vascular obstruction at baseline. Among patients with pulmonary embolism, a scintigraphic follow-up was pursued to assess the restoration of pulmonary perfusion over a 1-year period. We found that massive pulmonary embolism (vascular obstruction>or=50%) is a risk factor for mortality within the first few days after onset but, subsequently, has no significant effect on survival. The adjusted risk of death in patients with massive pulmonary embolism was 8-fold higher than in patients without embolism within the first day after the incident event. By contrast, the adjusted risk of death for patients with minor or moderate pulmonary embolism (vascular obstruction<50%) was no higher than in patients without embolism at any time after onset. Most of the patients who survived a year after pulmonary embolism showed a nearly complete restoration of pulmonary perfusion with a considerable improvement in arterial oxygenation. Four (1%) of the 320 patients with pulmonary embolism at presentation developed chronic thromboembolic pulmonary hypertension. These patients featured persistent large perfusion defects in sequential lung scans. Pulmonary embolism with vascular obstruction>or=50% is a strong, independent predictor of reduced short-term survival. This underscores the need for a prompt diagnosis of the disease. Monitoring the resolution of pulmonary embolism by lung scanning may prove useful in identifying patients with persistent perfusion abnormalities who may be at risk of chronic thromboembolic pulmonary hypertension.

Interatrial right-to-left shunt after lung surgery: diagnostic value of perfusion lung scanning.

A 61-year-old woman presented with platypnea and orthodeoxia after right pneumonectomy for lung cancer. A perfusion lung scan taken after tracer injection in the sitting position showed an extrapulmonary uptake of radioactivity consistent with a right-to-left shunt. Such extrapulmonary uptake was no longer evident when tracer was injected in supine posture. The authors emphasize the value of perfusion lung scanning in the assessment of patients with unexplained dyspnea after thoracic surgery.

A diagnostic strategy for pulmonary embolism based on standardised pretest probability and perfusion lung scanning: a management study.

Pulmonary embolism remains a challenging diagnostic problem. We developed a simple diagnostic strategy based on combination of assessment of the pretest probability with perfusion lung scan results to reduce the need for pulmonary angiography. We studied 390 consecutive patients (78% in-patients) with suspected pulmonary embolism. The pretest probability was rated low (<10%), intermediate (>10%, < or =50%), moderately high (>50%, < or =90%) or high (>90%) according to a structured clinical model. Perfusion lung scans were independently assigned to one of four categories: normal; near-normal; abnormal, suggestive of pulmonary embolism (wedge-shaped perfusion defects); abnormal, not suggestive of pulmonary embolism (perfusion defects other than wedge shaped). Pulmonary embolism was diagnosed in patients with abnormal scans suggestive of pulmonary embolism and moderately high or high pretest probability. Patients with normal or near-normal scans and those with abnormal scans not suggestive of pulmonary embolism and low pretest probability were deemed not to have pulmonary embolism. All other patients were allocated to pulmonary angiography. Patients in whom pulmonary embolism was excluded were left untreated. All patients were followed up for 1 year. Pulmonary embolism was diagnosed non-invasively in 132 patients (34%), and excluded in 191 (49%). Pulmonary angiography was required in 67 patients (17%). The prevalence of pulmonary embolism was 41% ( n=160). Patients in whom pulmonary embolism was excluded had a thrombo-embolic risk of 0.4% (95% confidence interval: 0.0%-2.8%). Our strategy permitted a non-invasive diagnosis or exclusion of pulmonary embolism in 83% of the cases (95% confidence interval: 79%-86%), and appeared to be safe.