Randomized trials, observational studies, and the illusive search for the source of truth

Research Concepts and Opportunities for Early-Career Investigators in Cardiac Surgery

Basic, translational or clinic, research is a key component of cardiac surgery. Understanding basic cellular and molecular mechanisms is key to improving patient outcomes, and cardiac surgical procedures must be compared with nonsurgical alternatives. However, guidance for early-career investigators interested in cardiac surgery research is limited. This opinion piece aims at providing basic guidance and principles based on the authors' experience.

The Impact of an Enrolment in Clinical Trial on Tolerance and Pathological Response for Patients Treated by Neoadjuvant MVAC Against an Invasive Bladder Cancer. A Retrospective Comparative Study

INTRODUCTION

MVAC (Methotrexate, Vinblastine, Adriamycin, and Cisplatin) neoadjuvant chemotherapy a standard treatment for invasive bladder cancer is associated with mainly haematological toxicities. Randomized clinical trials remain a gold standard for treatment outcomes and efficacy assessment. Patients enrolled in clinical trials are selected and tend to benefit from a stricter follow-up unlike everyday clinical practice patients. Conversely, real-life observational studies better define the effectiveness of treatments in clinical routine practice. The aim of this study is to analyse the impact of clinical trial monitoring on MVAC-related toxicities.

MATERIAL AND METHODS

Patients with an infiltrative localized bladder cancer treated by MVAC neoadjuvant chemotherapy between 2013 and 2019 were enrolled, and divided into 2 groups: patients included in a clinical trial namely "VESPER study" during their treatment and patients treated in clinical routine practice.

RESULTS

Out of 59 patients were enrolled in this retrospective study, 13 patients were included in a clinical trial. Clinical characteristics were similar between the 2 groups. Comorbidities were more frequent in the nonclinical trial group (NCTG). Completed 6 cures treatment proportion was higher in the clinical trial group (CTG) (69.2% vs. 50%). Yet, in this group, patients had more doses reduction (38.5% vs. 19.6%). The proportion of complete pathologic response was higher in patients enrolled in clinical trial (53.8% vs. 39.1%). Statistically, the expected stricter monitoring due to clinical trial enrolment had no impact on the complete pathologic response and clinically relevant toxicities.

DISCUSSION

When compared to conventional clinical practice, clinical trial enrolment induced no significant difference on the pathologic complete response or toxicity rate. Further large prospective studies are needed to confirm these data.

Comparing outcomes between coronary artery bypass grafting and percutaneous coronary intervention in octogenarians with left main or multivessel disease

Mechanisms of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) differ as CABG provides surgical collateralization and may prolong life by preventing future myocardial infarctions (MI). However, CABG benefits are unclear in octogenarians, where surgical risk is often perceived as higher and PCI is chosen more liberally. We performed a meta-analysis of studies comparing outcomes in octogenarians with left main or multivessel disease who underwent CABG or PCI. Primary outcome was late mortality (> 5 years). Secondary outcomes were perioperative mortality, MI, re-revascularization (R-R), acute renal failure (ARF), and stroke. Fourteen studies with 17,942 patients were included. CABG was associated with lower late mortality (hazard ratio, HR: 1.23, 95% confidence interval: CI 1.05-1.44, p < 0.01). In the pooled Kaplan-Meier analysis CABG showed significantly lower risk of death in the follow-up compared to PCI (HR: 1.08, 95%CI 1.02-1.41, p = 0.005). Landmark analyses confirmed the survival advantage of CABG over PCI after 21.5 months of follow-up (HR: 1.31, 1.19-1.44, p < 0.0001), but suggested advantage of PCI over CABG in the first 30-days (HR: 0.72, 0.64-0.82, p < 0.0001) and comparable survival from 1 to 21.5 months (HR: 0.98, 0.92-1.05, p = 0.652). We found lower risk for MI and R-R after CABG but higher perioperative mortality and no differences in ARF and stroke. CABG appears superior to PCI over time in octogenarians with complex CAD. This survival advantage is associated with fewer events of MI and R-R; however, it comes with an increased risk in perioperative mortality.

Comparing CABG and PCI across the globe based on current regional registry evidence

There is an ongoing debate whether coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) provide better results for the treatment of coronary artery disease (CAD). We aimed to evaluate the impact of CABG or PCI on long-term survival based on local reports from different regions in the world. We systematically searched MEDLINE selecting studies that compared outcomes for CABG or PCI as a treatment for CAD in the last 10 years. Reports without all-cause mortality, multi-national cohorts, hybrid revascularization populations were excluded. Qualifying studies were statistically compared, and their geographic location visualized on a world map. From 5126 studies, one randomized and twenty-two observational studies (19 risk-adjusted) met the inclusion criteria. The mean follow-up was 4.7 ± 7 years and 18 different countries were included. In 17 studies, CABG was associated with better survival during follow-up, six studies showed no significant difference, and no study favored PCI. Periprocedural mortality was not different in seven, lower with PCI in one, lower with CABG in three and not reported in 12 studies. In regional registry-type comparisons, CABG is associated with better long-term survival compared to PCI in most regions of the world without evidence for higher periprocedural mortality.

How to deal with nonsevere stenoses in coronary artery bypass grafting - a critical perspective on competitive flow and surgical precision

PURPOSE OF REVIEW

For invasive treatment of coronary artery disease (CAD), we assess anatomical complexity, analyse surgical risk and make heart-team decisions for percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). With PCI, treating flow-relevant lesions is recommended, and reintervention easily treats disease progression. For CABG, some stenoses may only be borderline or nonsevere despite a clear surgical indication. As reoperations are not easy, the question on how to address these lesions has been around from the start, but has never satisfactorily been answered.

RECENT FINDINGS

With a new mechanistic perspective, we had suggested that infarct-prevention by surgical collateralization is the main prognostic mechanism of CABG in chronic coronary syndrome. Importantly, the majority of infarctions arise from nonsevere coronary lesions. Thus, surgical collateralization may be a valid treatment option for nonsevere lesions, but graft patency moves more into focus here, because graft patency directly correlates with the severity of coronary stenoses. In addition, CABG may even accelerate native disease progression.

SUMMARY

We here review the evidence for and against grafting nonsevere CAD lesions, suggesting that patency of grafts (to moderate lesions) may be improved by increasing surgical precision. In addition, we must improve our ability to predict future myocardial infarctions.

Five-year outcomes in trials comparing transcatheter aortic valve implantation versus surgical aortic valve replacement: a pooled meta-analysis of reconstructed time-to-event data

OBJECTIVES

The incidence of outcomes in trials comparing transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) is expected to be different in the short and long term. We planned a meta-analysis of reconstructed time-to-event data from trials comparing TAVI and SAVR to evaluate their time-varying effects on outcomes.

METHODS

We performed a systematic review of the literature from January 2007 through September 2021 on Medline, Embase, the Cochrane Central Register of Controlled Trials and specialistic websites, including randomized trials with allocation to TAVI or SAVR that reported at least 1-year follow-up and that graphed Kaplan-Meier curves of end points. The comparisons were done with grouped frailty Cox models in a landmark framework and fully parametric models.

RESULTS

Seven trials were included (7770 participants). TAVI showed a lower incidence of the composite of death or stroke in the first 6 months [risk-stratified hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.56-0.77, P-value <0.001], with an HR reversal after 24 months favouring SAVR (risk-stratified HR 1.25; 95% CI 1.08-1.46; P-value 0.003). These outcomes were confirmed for all-cause death (risk-stratified HR after 24 months 1.18; 95% CI 1.03-1.35; P-value 0.01). TAVI was also associated with an increased incidence of rehospitalization after 6 months (risk-stratified HR 1.42; 95% CI 1.06-1.91; P-value 0.018) that got worse after 24 months (risk-stratified HR 1.67; 95% CI 1.24-2.24; P-value <0.001).

CONCLUSIONS

Although it could appear that there is no difference between TAVI and SAVR in the 5-year cumulative results, TAVI shows a strong protective effect in the short term that runs out after 1 year. TAVI becomes a risk factor for all-cause mortality and the composite end point after 24 months and for rehospitalization after 6 months.

Cardiac Surgery 2020 Reviewed

In 2020, nearly 30,000 published references appeared in the PubMed for the search term "cardiac surgery." While SARS-CoV-2 affected the number of surgical procedures, it did not affect outcomes reporting. Using the PRISMA approach, we selected relevant publications and prepared a results-oriented summary. We reviewed primarily the fields of coronary and conventional valve surgery and their overlap with interventional alternatives. The coronary field started with a discussion on trial data value and their interpretation. Registry comparisons of coronary artery bypass surgery (CABG) and percutaneous coronary intervention confirmed outcomes for severe coronary artery disease and advanced comorbidities with CABG. Multiple arterial grafting was best. In aortic valve surgery, meta-analyses of randomized trials report that transcatheter aortic valve implantation may provide a short-term advantage but long-term survival may be better with classic aortic valve replacement (AVR). Minimally invasive AVR and decellularized homografts emerged as hopeful techniques. In mitral and tricuspid valve surgery, excellent perioperative and long-term outcomes were presented for structural mitral regurgitation. For both, coronary and valve surgery, outcomes are strongly dependent on surgeon expertise. Kidney disease increases perioperative risk, but does not limit the surgical treatment effect. Finally, a cursory look is thrown on aortic, transplant, and assist-device surgery with a glimpse into the current stand of xenotransplantation. As in recent years, this article summarizes publications perceived as important by us. It does not expect to be complete and cannot be free of individual interpretation. We aimed to provide up-to-date information for decision-making and patient information.