Single versus dual anti-platelet therapy post transcatheter aortic valve implantation: a meta-analysis of randomized controlled trials

Incidence, Current Guidelines and Management of Gastrointestinal Bleeding after Transcatheter Aortic Valve Replacement: A Systematic Review

BACKGROUND

There is a significant increase in morbidity and mortality in patients complicated by major bleeding following transcatheter aortic valve replacement (TAVR). It has become more challenging to manage such complications when the patient needs to be on anticoagulation or antiplatelet agent post-procedure to prevent thrombotic/embolic complications.

METHODS

We systematically reviewed all available randomized controlled trials and observational studies to identify incidence rates of gastrointestinal bleeding post-procedure. After performing a systematic search, a total of 8731 patients from 15 studies (5 RCTs and 10 non-RCTs) were included in this review.

RESULTS

The average rate of gastrointestinal bleeding during follow-up was 3.0% in randomized controlled trials and 1.9% among observational studies.

CONCLUSION

Gastrointestinal bleeding has been noted to be higher in the RCTs as compared to observational studies. This review expands knowledge of current guidelines and possible management of patients undergoing TAVR.

Targeting Thymidine Phosphorylase With Tipiracil Hydrochloride Attenuates Thrombosis Without Increasing Risk of Bleeding in Mice

OBJECTIVE

Current antiplatelet medications increase the risk of bleeding, which leads to a clear clinical need in developing novel mechanism-based antiplatelet drugs. TYMP (Thymidine phosphorylase), a cytoplasm protein that is highly expressed in platelets, facilitates multiple agonist-induced platelet activation, and enhances thrombosis. Tipiracil hydrochloride (TPI), a selective TYMP inhibitor, has been approved by the Food and Drug Administration for clinical use. We tested the hypothesis that TPI is a safe antithrombotic medication. Approach and Results: By coexpression of TYMP and Lyn, GST (glutathione S-transferase) tagged Lyn-SH3 domain or Lyn-SH2 domain, we showed the direct evidence that TYMP binds to Lyn through both SH3 and SH2 domains, and TPI diminished the binding. TYMP deficiency significantly inhibits thrombosis in vivo in both sexes. Pretreatment of platelets with TPI rapidly inhibited collagen- and ADP-induced platelet aggregation. Under either normal or hyperlipidemic conditions, treating wild-type mice with TPI via intraperitoneal injection, intravenous injection, or gavage feeding dramatically inhibited thrombosis without inducing significant bleeding. Even at high doses, TPI has a lower bleeding side effect compared with aspirin and clopidogrel. Intravenous delivery of TPI alone or combined with tissue plasminogen activator dramatically inhibited thrombosis. Dual administration of a very low dose of aspirin and TPI, which had no antithrombotic effects when used alone, significantly inhibited thrombosis without disturbing hemostasis.

CONCLUSIONS

This study demonstrated that inhibition of TYMP, a cytoplasmic protein, attenuated multiple signaling pathways that mediate platelet activation, aggregation, and thrombosis. TPI can be used as a novel antithrombotic medication without the increase in risk of bleeding.

Single versus Dual Antiplatelet Therapy after Transcatheter Aortic Valve Implantation: A Systematic Review and Meta-Analysis

OBJECTIVES

Although dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is currently recommended in patients after transcatheter aortic valve implantation (TAVI), this practice is not supported by sufficient evidence. This study was performed to compare DAPT to single antiplatelet therapy (SAPT).

METHODS

An electronic search was completed of PubMed, Embase, Ovid Medline, Web of Science, and Cochrane Central Register of Controlled Trials. Studies comparing DAPT versus SAPT in patients undergoing TAVI were included.

RESULTS

Seven studies incorporating 1,445 patients were eligible for the present meta-analysis. There were no significant differences on 30-day all-cause mortality (OR 1.19, 95% CI 0.63-2.25, p = 0.593), 6-month all-cause mortality (OR 1.11, 95% CI 0.49-2.53, p = 0.796), or 1-year all-cause mortality (OR 1.19, 95% CI 0.63- 2.25, p = 0.593). DAPT was associated with an increased risk for 30-day (OR 2.91, 95% CI 1.85-4.58, p < 0.01), 6-month (OR 2.54, 95% CI 1.26-5.10, p < 0.001), and 1-year major and lethal bleeding (OR 2.65, 95% CI 1.04-6.77, p = 0.041) based on 896, 337, and 583 patients, respectively, compared to SAPT.

CONCLUSION

Compared to SAPT, DAPT was not shown to be superior in reducing thrombotic events, but presented an increased risk of major/life-threatening bleeding. More randomized controlled trials are needed to provide further evidence.

Cerebrovascular Events After Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) has emerged as an alternative less invasive treatment for patients with symptomatic severe aortic stenosis. Despite the technological development and knowledge improvement in recent years, neurological complications remain a concern, especially with the expansion of the technique toward younger and lower risk patients. Clinical cerebrovascular events have an important impact on patients' morbidity and mortality with a multifactorial origin. While cerebral microembolizations during TAVI is a universal phenomenon and embolic protection devices have been developed in an attempt to reduce them, their clinical utility remains unclear. We review the current evidence on cerebrovascular events associated with TAVI and potential preventive strategies.

Meta-Analysis of Studies Comparing Dual- Versus Mono-Antiplatelet Therapy Following Transcatheter Aortic Valve Implantation

Current guidelines recommend dual-antiplatelet therapy (DAPT) after transcatheter aortic valve implantation (TAVI), although some studies suggest mono-antiplatelet therapy is equally efficacious with an improved safety profile. We performed a meta-analysis of studies comparing DAPT with mono-antiplatelet therapy after TAVI. Study quality and heterogeneity were assessed using Jadad score, Newcastle-Ottawa Scale, and Cochran's Q statistics. Mantel-Haenszel odds ratios (ORs) were calculated using fixed effect models as the primary analysis. Eight studies including 2,439 patients met the inclusion criteria. At 30 days, DAPT was associated with an increased risk of all-cause mortality (OR 2.06, 95% confidence interval [CI] 1.34 to 3.18, p = 0.001), major or life-threatening bleeding (OR 2.04, 95% CI 1.60 to 2.59, p <0.001), and major vascular complications (OR 2.15, 95% CI 1.51 to 3.06, p <0.001). There was no difference in the rate of the combined end point of stroke or transient ischemic attack, or myocardial infarction. Outcome data up to 6 months were available in 5 studies; all-cause mortality and stroke were similar between groups, although major or life-threatening bleeding was more frequent with DAPT. In conclusion, in patients undergoing TAVI, DAPT is associated with increased risk at 30 days of all-cause mortality, major or life-threatening bleeding, and major vascular complications without a decrease in ischemic complications; at 6 months, the excess bleeding risk persisted. These data suggest a safety concern with DAPT and justify further investigation of the optimal antiplatelet therapy regimen after TAVI.