Giorgio Di Ricco

Value of transthoracic echocardiography in the diagnosis of pulmonary embolism: results of a prospective study in unselected patients

PURPOSE Echocardiography is advocated by some as a useful diagnostic test for patients with suspected pulmonary embolism (PE), but its diagnostic accuracy is unknown. The present study was undertaken to determine prospectively the sensitivity and specificity of transthoracic echocardiography in the diagnosis of PE. SUBJECTS AND METHODS We examined 110 consecutive patients with suspected PE. The study protocol included assessment of clinical probability, echocardiography, and perfusion lung scanning. Pulmonary angiography was performed in all patients with abnormal scans. As echocardiographic criteria to diagnose acute PE, we used the presence of any two of the following: right ventricular (RV) hypokinesis, RV end-diastolic diameter >27 mm (without RV wall hypertrophy), or tricuspid regurgitation velocity >2.7 m/sec. Clinical estimates of PE served as pretest probabilities in calculating, after echocardiography, the posttest probabilities of PE. RESULTS Pulmonary angiography confirmed PE in 43 (39%) of 110 patients. Echocardiographic diagnostic criteria for PE yielded a sensitivity of 56% and a specificity of 90%. For pretest probabilities of 10%, 50%, and 90%, the posttest probabilities of PE conditioned by a positive echocardiogram were 38%, 85%, and 98%, respectively. The posttest probabilities of PE conditioned by a negative echocardiogram were 5%, 33%, and 81%, respectively. CONCLUSIONS In unselected patients with suspected PE, transthoracic echocardiography fails to identify some 50% of patients with angiographically proven PE. Although echocardiographic findings of RV strain, paired with a high clinical likelihood, support a diagnosis of PE, the transthoracic echocardiography has to have a better sensitivity to be used as a screening test to rule out PE.

Fibrinolytic Effects of Urokinase and Heparin in Acute Pulmonary Embolism: A Randomized Clinical Trial

Dissolution of pulmonary emboli with heparin and urokinase is ascribed, respectively, to anticoagulation and fibrinolysis. Since truly independent assessment of these effects in man is lacking, we administered each drug alone. Fibrinogen and plasminogen plasma levels and the resolution of pulmonary emboli were measured in three randomized groups of 10 patients each: groups A and C infused with small repeated doses of urokinase and a large single dose of urokinase, respectively, and group B who received heparin. After 6 h of treatment, fibrinogen fell in all the groups, while, after 12 h, remained equally reduced in groups A and B and declined further in group C. Plasminogen behaved similarly. Up to 60 h, statistical analysis showed that these effects were related to timing and amounts of urokinase and heparin infusion. These observations suggest that heparin may induce a lytic state. As to signs of pulmonary emboli resolution, no differences between groups were found in lung perfusion and gas exchange recovery at any time (from 1 day to 1 year) and in pulmonary artery pressure reduction at 1 week. The greater angiographic and scintigraphic recovery observed with urokinase, versus heparin alone, after 1 day of treatment in the Urokinase Pulmonary Embolism Trial may be ascribed to a synergistic effect with urokinase of heparin administered during the diagnostic work-out. The indications of heparin and urokinase should be evaluated in the light of these results.

Venous Obstruction in Permanent Pacemaker Patients: An Isotopic Study

Isotope venography was used to study the venous circulation proximal to the superior vena cava in two groups of pacemaker patients, one with a single endo‐cavitary electrode and the other with multiple pacing catheters. A control group of patients without pacemakers was also studied. Numerous abnormalities were found, especially in the group with multiple electrodes. These findings suggest that venous obstruction is a common complication of endocardial pacing.

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.

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.

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.

Venous obstruction from temporary pacing through the subclavian vein

Abstract We describe a case of vein occlusion in a patient who had a temporary pacing lead inserted percutaneously through the subclavian vein.