Patients With Acute Pulmonary Embolism Fare Better With More-Targeted Thrombolysis

Patients admitted with an acute pulmonary embolism have improved in-hospital survival when treated with catheter-directed vs systemic thrombolysis, suggests a study published online August 26, 2015, ahead of print in Catheterization and Cardiovascular Interventions.

Apurva O. Badheka, MD, of Yale-New Haven Medical Center (New Haven, CT), and colleagues looked at data from the Nationwide Inpatient Sample on 110,731 patients hospitalized with a principal diagnosis of acute pulmonary embolism between 2010 and 2012. After exclusion of patients with other possible indications for thrombolysis—like deep vein thrombosis, STEMI, and ischemic stroke—there were 1,169 patients treated with systemic and 352 treated with catheter-directed thrombolysis.

Use of the catheter-directed approach increased by a relative 52% from 105 procedures in 2010 to 160 in 2012 (P < .001). Within the catheter-directed group, the in-hospital mortality rate remained unchanged at about 10% throughout the study period; intracranial hemorrhage (ICH) occurred in 0.95% of patients in 2010 and none in 2011 or 2012. 

In a propensity-score-matched analysis, which left 651 and 217 patients (mean age 58; 63% women) in the systemic and catheter-directed groups, respectively, more-targeted treatment was associated with reductions in in-hospital mortality (primary outcome) and a composite of in-hospital mortality or ICH. There were no differences in bleeding requiring transfusion or ICH alone, but acute renal failure requiring dialysis was more common in the catheter-directed group (table 1).

In a subgroup analysis, the benefit of catheter-directed thrombolysis in terms of mortality was seen specifically in elderly patients, with nonsignificant trends in other high-risk groups, including those with a high comorbidity burden, shock, and cardiopulmonary arrest.

Median length of stay was 7 days in both groups (P = .09), although median hospitalization cost was higher with catheter-directed thrombolysis ($24,714 vs $17,713; P < .0001).

Definitive Evidence Still Lacking

Guidelines state that thrombolysis should be used in patients with acute pulmonary embolism who are hemodynamically unstable or have substantial RV dysfunction or massive myocardial necrosis. Although systemic thrombolysis has been shown to have some benefit, it carries relatively high risks of major bleeding (9%) and hemorrhagic stroke (2%), limiting its use, according to the authors.

Catheter-directed thrombolysis has emerged as an alternative. Its use “is associated with more rapid permeation of the thrombolytic agent, allowing shorter infusion times,” Dr. Badheka and colleagues write. “This, coupled with local intraclot delivery of thrombolytic agent is postulated to result in lower bleeding complications.”

There are few studies evaluating the more-targeted approach, however. One study, ULTIMA, showed that catheter-directed thrombolysis—when added to IV heparin—improved RV function and was safe, with no deaths, major bleeding, or ICH.

The current study adds to the literature supporting the use of catheter-directed thrombolysis, but not every measure favored the technique. The observed increase in acute renal failure “could be due to contrast-induced nephropathy,” the authors say.

And the costs, though higher, “need to be weighed in against potential benefit in terms of superior clinical outcomes with this strategy,” they add. “Future studies with long-term follow-up will be crucial to understand the risk-adjusted economics of [catheter-directed thrombolysis] in terms of its impact on long-term mortality and rehospitalization.”

This study had several limitations, according to the authors, including the lack of information on the time from admission to thrombolysis, which fibrinolytic agent was used and at what dose, and use of anticoagulation, inferior vena cava filters, or vasopressors.

Thus, Dr. Badheka and colleagues say, an RCT comparing catheter-directed and systemic thrombolysis is needed to provide a definitive answer as to which strategy is better.

Source:

Patel N, Patel NJ, Agnihotri K, et al. Utilization of catheter-directed thrombolysis in pulmonary embolism and outcome difference between systemic thrombolysis and catheter-directed thrombolysis. Catheter Cardiovasc Interv. 2015;Epub ahead of print.

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