Sep 20, 2024 This Week in Cardiology Podcast

Summary

This episode of 'This Week in Cardiology' covers diverse cardiology topics, including potassium management after cardiac surgery, the safety of new cardiac devices, and disparities in preventive care. Dr. John Mandrola discusses key studies such as the Matterhorn trial on mitral valve repair, the Tight K trial on potassium replacement strategies, and the risks associated with early stopping of clinical trials. Additionally, he highlights the importance of post-market surveillance of medical devices and the healthcare disparities faced by marginalized populations. The episode underscores the need for long-term, evidence-based approaches to improve patient outcomes.

Takeaways

• 😀 **Listener Feedback on Matterhorn Trial**: The Matterhorn trial comparing transcatheter edge-to-edge repair (TEER) to mitral valve surgery sparked a discussion about the relevance of including common surgical complications like bleeding and atrial fibrillation (AF) in the trial outcomes.
• 😀 **Post-Surgery Atrial Fibrillation**: A study on potassium replacement strategies after cardiac surgery found no significant difference between tight and relaxed potassium control, suggesting that more aggressive potassium supplementation may not provide additional benefit and could be less cost-effective.
• 😀 **Medical Device Safety**: A study on class one recalls of cardiovascular devices highlighted the lack of clinical evidence for many devices approved through the 510(k) pathway, calling for greater post-market surveillance and caution when adopting new technologies.
• 😀 **Disparities in Preventive Care**: A study of insurance claim denials for preventive services found that individuals from lower-income and minoritized racial backgrounds face higher rates of denial, underscoring the need to address healthcare inequities.
• 😀 **Early Stopping of Clinical Trials**: The early stopping of clinical trials, particularly in chronic kidney disease studies, can lead to exaggerated treatment effects and less reliable findings, especially when fewer events are observed.
• 😀 **DAPA-CKD Trial**: The DAPA-CKD trial, which was stopped early, showed a significant reduction in kidney-related outcomes and all-cause mortality, but the cardiovascular mortality benefit was not observed, highlighting the impact of early trial stoppage on outcome interpretation.
• 😀 **Sham PVI Trial**: The Sham PVI trial, comparing pulmonary vein isolation (PVI) to a placebo procedure in atrial fibrillation, is a landmark study in AF ablation, and further insights from the investigators will be shared in an upcoming interview.
• 😀 **Challenges of Comparing Surgical and Device Procedures**: The Matterhorn trial and other studies highlighted the difficulty in comparing surgical versus device interventions, emphasizing that long-term outcomes should be considered when making treatment decisions.
• 😀 **Potassium and AF Prevention**: The Tight K RCT study suggests that maintaining potassium levels within normal range may be sufficient to prevent AF after surgery, challenging the conventional practice of aggressively increasing potassium levels to prevent arrhythmias.
• 😀 **Policy Implications of Device Approvals**: The findings from the class one recall study raise concerns about the FDA’s approval process for medical devices, suggesting that more stringent post-market surveillance is necessary to ensure patient safety and device effectiveness.

Q & A

What was the main topic of Dr. John Mandrola's discussion regarding the Matterhorn trial?

Dr. Mandrola discussed the Matterhorn trial, which compared transcatheter edge-to-edge repair versus mitral valve surgery for functional mitral regurgitation. He reflected on listener feedback that questioned whether expected complications like bleeding and atrial fibrillation should be counted as outcomes, highlighting the challenge in comparing two very different procedures.

What did the *Tight K* trial explore, and what were its findings?

The *Tight K* trial examined potassium replacement strategies after cardiac surgery. It found that a more relaxed potassium supplementation approach (maintaining potassium levels at 3.6 mmol/L) was non-inferior to the tighter strategy (4.5 mmol/L), with no increase in adverse outcomes. The relaxed approach also proved to be less costly and burdensome.

What concerns did Dr. Mandrola express regarding new cardiac devices?

Dr. Mandrola expressed caution about new cardiac devices, particularly those approved via the FDA's 510(k) pathway. He referenced several recalls of devices like ICD leads, which failed at higher rates than expected. He emphasized the need for post-market surveillance to ensure device safety and the importance of cautious adoption of new technologies.

What did the study published in *JAMA Network Open* reveal about disparities in preventive care?

The study showed that patients with lower incomes, less education, and those from minoritized racial and ethnic groups experienced higher rates of denials for preventive care services, such as screenings for diabetes, cholesterol, and cancer. Dr. Mandrola noted that reducing health disparities requires broader societal changes, not just healthcare policies.

What are the potential issues with stopping clinical trials early, as discussed in the podcast?

Dr. Mandrola highlighted that stopping clinical trials early can lead to unreliable data, overestimating the treatment effect due to fewer events being recorded. He pointed out that trials such as those involving SGLT2 inhibitors in chronic kidney disease faced challenges in interpreting results from early-stopped trials, where smaller data sets can introduce bias.

How did Dr. Mandrola view the importance of potassium levels in preventing atrial fibrillation (AF) after cardiac surgery?

Dr. Mandrola was surprised to learn that many clinicians believe maintaining high normal potassium levels can prevent AF after cardiac surgery. He emphasized that the *Tight K* trial provided evidence that a relaxed potassium replacement strategy (targeting 3.6 mmol/L) was equally effective, challenging the routine practice of aggressively maintaining higher potassium levels.

What is Dr. Mandrola's opinion on the safety of medical devices approved via the FDA’s 510(k) pathway?

Dr. Mandrola expressed concerns over devices approved through the FDA's 510(k) pathway, which only requires showing similarity to existing devices rather than proving safety and efficacy through rigorous trials. He mentioned that many devices approved this way later faced class one recalls, raising questions about their long-term safety and the adequacy of pre-market testing.

What was the conclusion of the *Tight K* trial regarding the cost-effectiveness of potassium supplementation strategies?

The *Tight K* trial concluded that a more relaxed potassium supplementation strategy (aiming for 3.6 mmol/L) was not only non-inferior in preventing AF after cardiac surgery but also more cost-effective and less burdensome than the more aggressive approach targeting 4.5 mmol/L.

What does Dr. Mandrola suggest is the real challenge in addressing health disparities in healthcare?

Dr. Mandrola suggests that healthcare disparities are deeply rooted in social determinants such as income, education, and race. While improving access to preventive care is important, he believes that reducing these disparities requires broader societal policy changes to address the gaps between rich and poor.

What was Dr. Mandrola’s takeaway from the study on device recalls published in *The Annals of Internal Medicine*?

Dr. Mandrola's takeaway was that many devices approved through the FDA’s 510(k) pathway, which lacked rigorous post-market surveillance, ended up being recalled for safety issues. He emphasized the importance of thorough post-market studies to catch safety issues early and cautioned against blindly adopting new technologies without considering long-term data.