Perioperative thrombocytopenia predicts poor outcome in patients undergoing transcatheter aortic valve implantation

Quantitative and Qualitative Platelet Derangements in Cardiac Surgery and Extracorporeal Life Support

Thrombocytopenia and impaired platelet function are known as intrinsic drawbacks of cardiac surgery and extracorporeal life supports (ECLS). A number of different factors influence platelet count and function including the inflammatory response to a cardiopulmonary bypass (CPB) or to ECLS, hemodilution, hypothermia, mechanical damage and preoperative treatment with platelet-inhibiting agents. Moreover, although underestimated, heparin-induced thrombocytopenia is still a hiccup in the perioperative management of cardiac surgical and, above all, ECLS patients. Moreover, recent investigations have highlighted how platelet disorders also affect patients undergoing biological prosthesis implantation. Though many hypotheses have been suggested, the mechanism underlying thrombocytopenia and platelet disorders is still to be cleared. This narrative review aims to offer clinicians a summary of their major causes in the cardiac surgery setting.

Predictors of short-term thrombocytopenia after transcatheter aortic valve implantation: a retrospective study at a single Japanese center

OBJECTIVE

Thrombocytopenia is common after transcatheter aortic valve implantation (TAVI) and is associated with mortality and major complications, although the underlying mechanisms are unclear. This retrospective single-center study aimed to identify factors associated with the decrease in platelet count (DPC) after TAVI in Japanese patients. Patients with severe aortic valve stenosis who underwent transfemoral TAVI between March 2014 and August 2019 were grouped according to DPC values of < 50% or ≥ 50% (DPC = 100% × [baseline platelet count-nadir platelet count]/[baseline platelet count]). Multivariable logistic regression analysis was performed to identify factors associated with a DPC of ≥ 50%.

RESULTS

Among the 131 patients who underwent transfemoral TAVI, 74 patients (56%) had a DPC of ≥ 50%, and 57 patients (44%) had a DPC of < 50%. Significant risk factors for a DPC of ≥ 50% were older age, lower body mass index (BMI), and use of balloon-expandable valves (BEV). The multivariable analysis revealed that a DPC of ≥ 50% was independently predicted by low BMI (adjusted odds ratio: 0.884, 95% confidence interval: 0.785-0.997; P = 0.039) and BEV use (adjusted odds ratio: 3.014, 95% confidence interval: 1.003-9.056; P = 0.045). Platelet count monitoring after TAVI, especially when using BEV devices, is essential for Japanese patients with low BMI.

Predictor and Mid-Term Outcome of Clinically Significant Thrombocytopenia After Transcatheter Aortic Valve Selection

BACKGROUND

The frequency and predictors of thrombocytopenia after transcatheter aortic valve implantation (TAVI) are unclear.Methods and Results:This study enrolled 342 patients undergoing TAVI (245 with a percutaneous transfemoral approach, 65 with transfemoral surgical cutdown, and 32 with a non-transfemoral approach). Balloon-expandable and self-expanding valves were implanted in 235 and 107 patients, respectively. Platelet counts started to drop immediately, reaching a nadir 2-4 days after TAVI. Clinically significant thrombocytopenia (CSTP) was defined as a platelet count ≤50×10⁹/L at the time of the nadir or both a platelet count between 80 and 51×10⁹/L and a decrease in platelet count ≥50%. CSTP occurred in 16.7% patients. Approach site and TAVI valve selection significantly predicted CSTP. In multivariate analysis, independent predictors of CSTP were liver cirrhosis (odds ratio [OR] 7.22; 95% confidence interval [CI] 1.05-49.82), baseline platelet count ≤120×10⁹/L (OR 2.98; 95% CI 1.20-7.38), multiple blood transfusions (OR 4.03; 95% CI 1.72-9.41), and the use of balloon-expandable valves (OR 2.38; 95% CI 1.04-5.46). Kaplan-Meier survival analysis with a generalized Wilcoxon test revealed that mid-term (2 years) mortality was greater for patients with than without CSTP (31.4% vs. 15.5%; P=0.008).

CONCLUSIONS

TAVI-related CSTP was not rare and was associated with poor mid-term outcomes. CSTP was not only caused by patients' comorbidities and TAVI complications, but also related to TAVI procedural factors.

Impact of chronic thrombocytopenia on in-hospital outcomes and healthcare resource utilization after transcatheter aortic valve replacement

BACKGROUND

There is little data on the impact of chronic thrombocytopenia (CTP) on outcomes after transcatheter aortic valve repair (TAVR). Most studies are from single centers and mostly focused on postprocedure thrombocytopenia.

OBJECTIVES

This study sought to report on the impact of CTP (>1 year) on in-hospital outcomes and healthcare resource utilization after TAVR.

METHODS

From the National Inpatient Sample (NIS) between 2012 and 2015, we identified patients with CTP who underwent TAVR. A 1:1 propensity-matched cohort was created to examine in-hospital outcomes in patients with and without CTP. The primary outcome was in-hospital mortality. Secondary outcomes included postprocedure complications, length of stay, total cost, and discharge disposition.

RESULTS

A matched pair of 4,300 patients with and without CTP were identified. Patients with CTP had higher in-hospital mortality as compared to no CTP patients (6.0 vs. 3.3%, p-value .007), increased postprocedure hemorrhage, platelet and blood transfusion, vascular complications, postop sepsis, and acute kidney injury. With regards to resource utilization, CTP patients had a longer length of stay, higher total cost and were more likely to be discharged to a facility (34.1 vs. 27.6%) other than home (All, p-value <.001). Subanalysis, however, revealed this difference in resource utilization was seen when patients developed postprocedure complications.

CONCLUSION

This study demonstrated higher risk of in-hospital mortality, perioperative complications, and healthcare resource utilization in patients with baseline CTP undergoing TAVR. Further studies are required to investigate ways to improve the management of these patients.

Peri-procedural thrombocytopenia after aortic bioprosthesis implant: A systematic review and meta-analysis comparison among conventional, stentless, rapid-deployment, and transcatheter valves

BACKGROUND

Thrombocytopenia has been shown to occur soon after surgical biological aortic valve replacement (AVR), and recently reported also after transcatheter valve implantation (TAVI). The mechanism underlying this phenomenon is still unknown, and its clinical impact on the peri-operative outcome has been poorly investigated.

METHODS

A systematic review and a meta-analysis of all available studies reporting data about peri-procedural thrombocytopenia on isolated bio-AVR, comparing rapid-deployment (RDV), stentless (stentless-AVR), and TAVI vs. stented (stented-AVR) valves, have been performed.

RESULTS

Fifteen trials (2.163 patients) were included in the meta-analysis. Perioperative platelet reduction ranged from 35% to 55% in stented-AVR, from 60% to 77% in stentless-AVR, from 53% to 60% in RDV, and from to 21% to 72% in TAVI (apparently, balloon-expandable valves more frequently associated to thrombocytopenia). Stented-AVR required more red blood cells transfusion than stentless-AVR (P < 0.0001), whereas no difference has been found between RDV and stented-AVR. Platelet transfusion rate was very low in all surgical groups. No difference has been found in RDV and stentless-AVR vs. stented-AVR, in terms of reoperation for bleeding, and length-of-intensive care unit or hospital stay.

CONCLUSIONS

Thrombocytopenia-related major adverse events were mainly reported in TAVI patients, whereas clinically meaningless in surgical patients. Transient peri-procedural thrombocytopenia is common after bio-AVR, regardless of prosthesis's type or implant modality. It should receive appropriate monitoring and focused investigations.

Autoimmune Heparin-Induced Thrombocytopenia after Transcatheter Aortic Valve Implantation: Successful Treatment with Adjunct High-Dose Intravenous Immunoglobulin

We describe a rare case of autoimmune heparin-induced thrombocytopenia after transcatheter aortic valve implantation in which antibodies against platelet factor 4/heparin have led to platelet activation even after heparin cessation, causing a delayed drop in platelet count to below 20 × 10 ⁹ /L. Most interestingly, platelet count rapidly improved after intravenous immunoglobulin treatment and no new thromboembolic complications were observed with further anticoagulation with rivaroxaban.