A New Paradigm in Managing Ventricular Septal Rupture After Myocardial Infarction

In the high-risk setting of emergency surgery for post-myocardial infarction ventricular septal rupture (post-MI VSR), support with a temporary microaxial transvalvular left ventricular assist device (tVAD) can serve as a bridge to recovery or advanced therapy in appropriate patients and as an aid in determining futility in others. So finds a retrospective Cleveland Clinic study evaluating tVAD support in patients with post-MI VSR published in JTCVS Techniques (Epub 2024 Sep 4).

“We wanted to know when and how we might be able to safely delay operating on patients with cardiogenic shock and friable myocardium, and the surgical tVAD provided the answer,” says study co-author Edward Soltesz, MD, MPH, Surgical Director of Cleveland Clinic’s Kaufman Center for Heart Failure and Recovery. “It offered an opportunity to stabilize patients and ascertain if they needed advanced heart failure therapies, if multiorgan system failure signaled futility or if it was reasonable to perform nonemergency surgical closure of the septal rupture on a delayed basis.”

Study backdrop

VSR is a rare complication of MI, and the spectrum of its presentations is wide, from few or no symptoms to life-threatening cardiogenic shock. While timing and efficacy of treatment varies, emergency surgery has been the gold standard, according to guidelines from the American College of Cardiology/American Heart Association. The procedural mortality rate is high, due in part to the fragility of the infarcted myocardium and preoperative acuity. Without the repair, patients are unlikely to survive.

Preoperative use of an intra-aortic balloon pump or extracorporeal membrane oxygenation to improve hemodynamic stability in patients with VSR has been found to be suboptimal. Several recent case studies have shown promising results with tVAD use as a bridge to post-MI VSR repair.

The new report describes the Cleveland Clinic experience with tVAD support in the treatment of post-MI VSR, an effort focused on shifting the paradigm from emergency definitive surgery to tailored treatment. “Our hypothesis,” explains cardiothoracic surgeon and study co-author Nicholas Smedira, MD, MBA, “was that the device could be used as a bridge to delayed surgery (to buy time to optimize repair security and end-organ recovery), as a bridge to advanced therapies or for palliation to decisions about futility.”

Essentials of study design and results

Characteristics, hemodynamics, intraoperative details and postoperative outcomes were assessed among 10 patients with post-MI VSR who underwent tVAD at Cleveland Clinic between December 2019 and July 2023. All patients were male; their median age was 66 years (range, 55-77). Acuity varied: six of the 10 patients had acute kidney injury, five had right ventricular failure, five had shock liver and two had in-hospital cardiac arrest.

Two patients died prior to VSR repair. Eight patients underwent surgery (7 open, 1 percutaneous); tVAD support was provided prior to six of the seven open procedures. In one case, the device was inserted perioperatively during emergency open repair of a right ventricular rupture. Median time from diagnosis of post-MI VSR to tVAD implantation was 2.5 days (range, 1-16).

Preoperative tVAD support was associated with improvements in median values for hemodynamics and end-organ function. From device insertion to repair:

• Shunt fraction decreased, from 2.6 to 1.8
• Cardiac index increased, from 1.5 to 3.1 mL/min/m²
• Pulmonary capillary wedge pressure decreased, from 25 to 16 mm Hg
• Central venous pressure decreased, from 14 to 12 mm Hg
• Creatinine decreased, from 1.5 to 1.2 mg/dL
• Lactate decreased, from 1.3 to 0.7 mmol/L

Median time from diagnosis of post-MI VSR to repair was 15 days (range, 13-18). The surgical approach was via atriotomy in four patients, left ventriculotomy in two patients and right ventricular access in one patient. None of the patients had a residual VSR, and there were no operative deaths.

Although a previous case report about tVAD support raised concerns over shunt reversal (right to left), the authors observed only improvements in left-to-right shunting. They note, however, that frequent evaluation of shunting is necessary in patients who receive the device.

“Analogous to its use in cardiogenic shock, tVAD support acted as a bridge to recovery in selected patients, enabling delayed surgical intervention after determination that there was sufficient residual cardiac function to undergo a repair without advanced therapies,” Dr. Smedira observes. “In the patients with intraoperative tVAD insertion and emergency repair, the septal tissue was especially poor and the tVAD reduced the left ventricular end diastolic pressure on the patch, allowing the repair to heal without dehiscence.”

“From the critical care cardiology perspective, these patients used to have a significantly high mortality either prior to surgery or perioperatively,” adds study co-author Ran Lee, MD, Co-Director of the Heart Failure Intensive Care Unit at Cleveland Clinic. “Use of the tVAD has led to a paradigm shift in stabilizing these almost-prohibitive-risk individuals and allowing them to become candidates for definitive surgical repair.”

Dr. Soltesz also notes the role that tVAD played in one patient, as a bridge to advanced therapies. “Temporizing with tVAD allowed for a stable, but expedited, advanced therapy evaluation, improving candidacy and reducing operative risk for durable LVAD implantation,” he says. “Our results support a paradigm shift in the treatment of post-MI VSR from emergency to nonemergency surgery following initial tVAD support, which has now become our default practice at Cleveland Clinic.”

Clinical benefits and the essential role of ICU expertise

Key clinical benefits of the new tVAD paradigm for post-MI VSR, as summarized by the authors, include:

• Enabling delayed, nonemergency surgical repair in appropriate candidates
• Improving hemodynamics and end-organ function
• Unloading the left ventricle to promote myocardial recovery while assessing residual heart function and need for advanced therapies
• Preventing intensive care unit deconditioning (extubation and ambulation)
• Allowing time for antiplatelet drug washout

The authors emphasize that successful tVAD use in this setting is predicated on meticulous medical management. “In the ICU, we still must remain vigilant for end-organ dysfunction in this extreme form of cardiogenic shock,” notes Dr. Lee. “This involves assessing each organ system in a systematic manner to avoid — and, in many cases, try to reverse — worsening sequelae and prevent death. For example, many individuals need additional continuous IV medications to facilitate diuresis and afterload reduction to further mitigate the left-to-right shunting that occurs. Some cases may require initiation of renal replacement therapies. Other management goals that are paramount to good outcomes on the perioperative and postoperative side are protecting the lungs from injury if the patient is on a ventilator and assuring a consistent intact neurologic status while minimizing ICU delirium. Both critical care expertise and proper use of the tVAD have been uniquely and newly suited to care for this patient population in whom mortality previously was almost guaranteed.”

Disclosure: Dr. Soltesz reports having received honoraria from Abiomed, which markets the tVAD used in the patients involved in this study.