May 15, 2020 This Week in Cardiology Podcast

John M. Mandrola, MD


May 15, 2020

Please note that the text below is not a full transcript and has not been copyedited. For more insight and commentary on these stories, subscribe to the This Week in Cardiology podcast.

In This Week’s Podcast

For the week ending May 15, 2020, John Mandrola, MD comments on the following news and features stories.

COVID Update

When I recorded last week, there were 1.26 million cases in the United States. Today there are 1.5 million. The rate of growth of 1.15x is about the same. You expect more cases with the increase in testing, now up to 10 million tests. US deaths last week were 75,000, today 86,000. That growth rate of 1.14x is about the same as well.

This is looking like the new normal. For about a month straight we’ve seen slightly increasing numbers of cases and deaths. It is not great news; I wish the virus never came; but I think it’s the new normal, until a) herd immunity, or b) a vaccine.

Globally, there are now 4.5 million COVID cases with 1.7 million recovered. I continue to worry about Brazil, which yesterday reported 14,000 cases in one day. India remains a standout with only 2 deaths per million. South Australia has reported days with zero new cases. I also keep an eye on Sweden, with their more lax social distancing. Their 350 COVID deaths per million is less than the United States, Spain, the UK, Italy, France, Belgium, and the Netherlands.

Final note on PCR tests: An Indiana University group publishing in JAMA studied a small group of patients and health care workers (HCW) in a pediatric dialysis unit. Over 3 weeks, 44% of 25 HCW seroconverted for COVID antibodies. Only two had symptoms and both of these had negative nasal swabs. My friends, I am pretty sure the false negatives of PCR testing is a big problem.

Anticoagulation and COVID-19

While there is still much to learn about acute COVID-19 illness, it is clear that thrombotic complications are common. If that is true, it makes perfect sense to consider anti-thrombotic drugs, like anticoagulants.

The best way to answer the question of whether or not anticoagulation is beneficial in patients with COVID-19 is to randomize patients to either anticoagulation or not. In the absence of RCTs, which take time and energy, the temptation is to compile observations after the fact. Observations are not useless but they are fraught with bias and if you aren’t careful, you can be fooled.

Here I report on a research letter published in the Journal of the American College of Cardiology (JACC), a highly influential medical journal. This was a retrospective report on 2800 patients with COVID-19 admitted to the Mt. Sinai System in New York.

The authors studied the association of anticoagulation and in-hospital mortality. They reported in-hospital mortality for patients treated with anticoagulation was 23%, with a median survival of 21 days, compared with 23% mortality but survival of just 14 days in patients who did not receive anticoagulation.

For patients on ventilators, a subset of about 370 patients, in-hospital mortality was 29% for those treated with anticoagulation vs 63% for patients who did not receive anticoagulation. That’s a 200% better survival for those who received anticoagulation.

The second author of the paper is Dr Val Fuster himself – the editor in chief of JACC. He was clearly impressed with the strength of the associations in this study. He told Patrice Wendling of the | Medscape Cardiology that “I can tell you any family of mine who will have this disease absolutely will be on antithrombotic therapy and, actually, so are all of the patients at Mount Sinai now."

But this was an utterly flawed study. The fatal flaw was immortal time bias. Patients who received anticoagulation at any time in their hospitalization had to be alive for 3, 4, 5, or more days before anticoagulation, whereas patients who did not receive anticoagulation could die at any time. The time before a person received anticoagulation is the immortal time.

By making causal claims from flawed observational data, equipoise is shredded. Dr Fuster may be right, full-dose anticoagulation may be beneficial, but the only way to know is to do the RCTs.

Heart Rhythm Society Meeting: Implantable Cardioverter Defibrillator

If not for the pandemic, last week would have been the HRS meeting in San Diego. There were some notable studies. The biggest news was a Dutch trial called PRAETORIAN, which compared the standard transvenous ICD (TV-ICD) to the new subcutaneous ICD (S-ICD).

PRAETORIAN was appropriately set up as a non-inferiority trial. The primary outcome was major ICD-related adverse events—inappropriate shocks and device -related complications.

About 400 patients were in each group. The primary endpoint was a composite of inappropriate shocks plus ICD-related complications; both were 15% and thus, the S-ICD was noninferior.

Inappropriate shocks were higher at 10% for S-ICD vs 7% for TV-ICD. Device-related complications were 10% for TV-ICD vs 6% for the S-ICD. Lead problems were 6.6% in the TV-ICD arm vs 1.4 in the S-ICD arm. Death from any cause was in absolute terms 3.3% higher in the S-ICD arm; the p-value was 0.20 so not significant; adjudicated sudden deaths were similar in each arm.

Thus, the S-ICD was found noninferior to the TV-ICD. Inappropriate shocks were numerically higher but not significant. Lead related problems were less in S-ICD. The authors say the S-ICD should be considered in all patients in need of an ICD without pacing indication.

For us slow adopters, this trial is a nice addition. I see its use in younger patients with non-ischemic causes of sudden death. Channelopathies, aborted sudden death, young people with nonischemic cardiomyopathy. Where I will remain cautious is in people with ischemic cardiomyopathy or significant scar.

This study should not be cited as evidence that S-ICD avoids long-term lead problems of the TV-ICD. Rather, the S-ICD did better with short-term lead implant issues. Another notable –almost 5% of the S-ICD group had to be converted to TV system. That raises cost issues.

Heart Rhythm Society Meeting: Left Bundle Branch Pacing

Another paper at HRS involved LBB pacing. The late-breaking study was from from Pugal Vijayaramen from Geisinger and others in Spain, Florida, Brazil, and Poland. This was a noncontrolled case series of about 325 patients with CRT pacing indication, with successful LBB pacing in 277 and non-successful in 48 patients.

The thresholds were great as were the sensing parameters. The R wave was 10. Outcomes like QRS duration, NYHA class, ejection fraction, left ventricular end diastolic diameter, all significantly improved in those who had LBB pacing. Successful LBB pacing was a predictor of CRT response

This is, of course, a beginning study. It is observational, has no comparison with BiV or His bundle pacing and there is no data on longterm lead performance. But I think there is something here. We need more data, however, and we need to be cautious.


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