Carolina Bauleo

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

Abstract: 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 ≥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 ≥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.

Fibrin Resistance to Lysis in Patients with Pulmonary Hypertension Other Than Thromboembolic

RATIONALE Reportedly, fibrin isolated from patients with chronic thromboembolic pulmonary hypertension (CTEPH) is resistant to lysis. Persistence of regions within the fibrin beta chain, which mediate cell signaling and migration, could trigger the organization of pulmonary thromboemboli into chronic intravascular scars. OBJECTIVES Ascertain whether fibrin resistance to lysis occurs in patients with pulmonary hypertension (PAH) other than CTEPH, and in those with prior pulmonary embolism (PE) and no pulmonary hypertension. METHODS Fibrinogen was purified from 96 subjects (17 with CTEPH, 14 with PAH, 39 with prior PE, and 26 healthy control subjects) and exposed to thrombin to obtain fibrin clots. Plasmin-mediated cleavage of fibrin beta chain was assessed hourly over a 6-hour period by polyacrylamide gel electrophoresis. Fibrin band intensity was measured by densitometry of stained gels. Data were normalized to the band intensity of the undigested protein. MEASUREMENTS AND MAIN RESULTS By 1 hour of digestion, fibrin band intensity had decreased by a median of 25% (interquartile range [IQR], 20 to 27%) in control subjects, and by 15% (IQR, 11 to 18%) in patients with prior PE (P < 0.0001). The 1-hour median reduction in band intensity was 2% (IQR, 1 to 3%) in CTEPH, and 4% (IQR, 2 to 7%) in PAH (P < 0.0001 vs. control subjects and PE). The decline in fibrin band intensity remained significantly different among the four groups up to 6 hours (P < 0.0001). CONCLUSIONS Fibrin resistance to lysis occurs in pulmonary hypertension other than CTEPH and, to a smaller extent, in patients with prior PE and no pulmonary hypertension.

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%, ≤50%), moderately high (>50%, ≤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.

Accuracy of chest radiography in predicting pulmonary hypertension: a case-control study.

OBJECTIVE To assess the accuracy of chest radiography (CXR) in predicting pulmonary hypertension (PH). METHODS We studied 108 consecutive patients with suspected PH who underwent right heart catheterization (RHC). All were PH treatment naives. Hemodynamic criteria included a mean pulmonary artery pressure >25 mmHg at rest, and a mean pulmonary wedge pressure <15 mmHg. Postero-anterior and lateral CXR were obtained shortly before RHC. To avoid a selection bias which could be introduced by examining only patients with suspected PH, we included in the analysis the CXR of 454 additional patients with different diagnosis: 57 with left heart failure (LHF) and pulmonary venous hypertension at RHC, 197 with chronic obstructive pulmonary disease, and 200 non-obstructed controls. CXR were examined independently by 4 raters, who were blinded to clinical, hemodynamic, and spirometric data. The diagnosis of PH was made if a prominent main pulmonary artery was associated with anyone of: isolated enlargement of right ventricle, right descending pulmonary artery >16 mm in diameter, pruning of peripheral pulmonary vessels. RESULTS Eighty-two patients had PH confirmed at RHC. Weighted sensitivity of CXR was 96.9% (95% confidence interval, 94.9 to 98.2%), and weighted specificity 99.8% (95% confidence interval, 99.6 to 99.9%). By considering the 165 patients who underwent RHC, weighted sensitivity of CXR was unchanged, and weighted specificity decreased to 99.1%. None of the patients with PH were misclassified as having LHF, and vice versa. CONCLUSIONS CXR is accurate in predicting PH. It may aid clinicians in selecting patients with suspected PH for hemodynamic ascertainment.

Non-invasive diagnosis of pulmonary embolism

Pulmonary embolism (PE) remains a challenging diagnostic problem because it mimics other cardiopulmonary disorders. Pulmonary angiography is still the reference standard for diagnosing PE but it is costly, invasive and not readily available. Non-invasive diagnostic strategies have therefore been developed to forego pulmonary angiography in patients suspected of having PE. Ventilation/perfusion lung scanning is, at present, the most widely used non-invasive diagnostic test for PE. A high probability ventilation/perfusion scan (segmental or greater perfusion defects with normal ventilation) warrants the institution of anticoagulant therapy especially when paired with high clinical suspicion of PE. Yet, only a minority of patients with confirmed PE have high probability ventilation/perfusion scans. Ventilation/perfusion abnormalities other than those of the high probability scan should be regarded as non-diagnostic. Under these circumstances, documentation of deep vein thrombosis by non-invasive leg testing warrants anticoagulation without the need for angiography. However, a single negative venous study result does not permit to rule out PE in patients with non-diagnostic ventilation/perfusion scans. Results of a recent prospective study indicate that accurate diagnosis or exclusion of PE is possible with perfusion lung scanning alone (without ventilation imaging). Combining perfusion lung scanning with clinical assessment helps to restrict the need for angiography to a minority of patients with suspected PE.