Fast vs. ultraslow thrombolytic infusion regimens in patients with obstructive mechanical prosthetic valve...

Thrombolysis is an alternative to surgery for mechanical prosthetic valve thrombosis (MPVT). Randomized clinical trials have yet to test the safety and efficacy of a proposed ultraslow thrombolytic infusion regimen.

This single-centre, open-label, pilot randomized clinical trial randomized adult patients with acute obstructive MPVT to an ultraslow thrombolytic regimen [25 mg of recombinant tissue-type plasminogen activator (rtPA) infused in 25 h] and a fast thrombolytic regimen (50 mg of rtPA infused in 6 h). If thrombolysis failed, a repeated dose of 25 mg of rtPA for 6 h was administered in both groups up to a cumulative dose of 150 mg or the occurrence of a complication. The primary outcome was a complete MPVT resolution (>75% fall in the obstructive gradient by transthoracic echocardiography, <10° limitation in opening and closing valve motion angles by fluoroscopy, and symptom improvement). The key safety outcome was a Bleeding Academic Research Consortium type III or V major bleeding. Overall, 120 patients, including 63 (52.5%) women, at a mean age of 36.3 ± 15.3 years, were randomized. Complete thrombolysis success was achieved in 51 patients (85.0%) in the ultraslow-regimen group and 47 patients (78.3%) in the fast-regimen group [odds ratio 1.58; 95% confidence interval (CI) 0.25-1.63; P = 0.34]. One case of transient ischaemic attack and three cases of intracranial haemorrhage (absolute risk difference -6.6%; 95%CI -12% -0.3%; P = 0.07) were observed only in the fast-regimen group.

The ultraslow thrombolytic regimen conferred a high thrombosis resolution rate without major complications. Such findings should be replicated in more adequately powered trials.