Aspiring Medical Student and current Critical Care RN. Enjoys everything outdoors but can also be found inside nerding out on her medical education artwork.
The Pre-brief
A 70 year old female presents to the emergency department for worsening shortness of breath. Her symptoms have been progressive for 1 week. She has a history of hypertension and is a current smoker. On exam, heart rate is 60 bpm, blood pressure 80/60 mm Hg, respiratory rate 28 breaths/min, and pulse oximetry 91% on 2 L nasal cannula. Physical exam reveals crackles in the bilateral lung fields but otherwise is unremarkable. EKG is a normal sinus rhythm with q-waves in the anterior leads. Bedside ultrasound reveals the following:
There is a large ventricular septal defect (VSD) with left to right shunt. An intra-aortic balloon pump (IABP) is placed, though the patient progresses to right heart failure and systemic hypoperfusion requiring veno-arterial ECMO.
Mechanical complications of AMI can include VSD, papillary muscle rupture, and free wall rupture. Though rare, they can present like common ‘CHF exacerbations,’ but require radically different and aggressive therapy aside from BiPAP and diuretics.
VSDs are uncommon in the reperfusion era, occurring in 0.3% of patients following acute myocardial infarction (AMI). These typically develop 3-5 days following AMI, and symptoms can range from asymptomatic to cardiogenic shock. Therapeutic options include medical therapy, cardiac surgery, or percutaneous transcatheter closure.
Medical therapy has a mortality rate approaching 80%, and as such is limited to those with benign defects or those who are not surgical candidates. More invasive therapies prior to surgery include methods of mechanical circulatory support. An intra-aortic balloon pump, via afterload reduction, will lessen left-to-right shunt and improve systemic blood pressure. A variety of mechanical circulatory support devices can offer a bridge to closure. In this case, escalation to V-A ECMO was used given our patients degree of multiorgan system failure.
There are two corrective approaches to ischemic VSDs: cardiac surgery or percutaneous transcatheter closure (TCC). Both options have pros and cons. Cardiac surgery had been the standard of care prior to the advent of TCC, though both approaches have similar mortality outcomes (50-60%). TCC seems preferable in those that are a high surgical risk and have technically amenable VSDs. The ideal closure approach needs to be personalized to patient and VSD specifics. Please see the following figure discussing the pros and cons of different approaches
Timing of intervention, whether surgery or TCC, is also to be considered. Early closure (less than 7 days) is associated with increased mortality, though this is likely due to survival bias. There is also concern that early surgical repair is less likely to be successful given the presence of ischemic, friable tissue.
Case Conclusion:
The patient stabilized on V-A ECMO and all associated organ failure resolved. IABP was maintained as a left ventricle vent. (“Venting the LV” is a strategy to reduce LV end diastolic pressure (EDP) in the face of the retrograde perfusion of the ECMO return cannula. In a patient with a VSD, lowering the LV EDP will lessen the shunt fraction.) Given high surgical risk, TCC was successfully completed on day 11. There was a residual apical VSD that did not have hemodynamic consequences.
The Debrief
- VSD is an uncommon but morbid mechanical complication of acute myocardial infarction
- Mechanical circulatory support can offer a bridge to repair
- Repair options include cardiac surgery and transcatheter closure. The ideal approach and timing is decided on a case by case basis
- The American Heart Association recently published a guideline for mechanical complications of AMI, give it a read
References
- Jones, B. M., Kapadia, S. R., Smedira, N. G., Robich, M., Tuzcu, E. M., Menon, V., & Krishnaswamy, A. (2014). Ventricular septal rupture complicating acute myocardial infarction: a contemporary review. European heart journal, 35(31), 2060-2068.
- Omar, S., Morgan, G. L., Panchal, H. B., Thourani, V., Rihal, C. S., Patel, R., … & Beohar, N. (2018). Management of post‐myocardial infarction ventricular septal defects: A critical assessment. Journal of interventional cardiology, 31(6), 939-948.
- Menon, V., Webb, J. G., Hillis, L. D., Sleeper, L. A., Abboud, R., Dzavik, V., … & SHOCK Investigators. (2000). Outcome and profile of ventricular septal rupture with cardiogenic shock after myocardial infarction: a report from the SHOCK Trial Registry. Journal of the American College of Cardiology, 36(3S1), 1110-1116.
- Rob, D., Špunda, R., Lindner, J., Rohn, V., Kunstýř, J., Balík, M., … & Bělohlávek, J. (2017). A rationale for early extracorporeal membrane oxygenation in patients with postinfarction ventricular septal rupture complicated by cardiogenic shock. European journal of heart failure, 19, 97-103.
- Arnaoutakis, G. J., Zhao, Y., George, T. J., Sciortino, C. M., McCarthy, P. M., & Conte, J. V. (2012). Surgical repair of ventricular septal defect after myocardial infarction: outcomes from the Society of Thoracic Surgeons National Database. The Annals of thoracic surgery, 94(2), 436-444.
- Damluji, A. A., van Diepen, S., Katz, J. N., Menon, V., Tamis-Holland, J. E., Bakitas, M., … & American Heart Association Council on Clinical Cardiology; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Cardiovascular Surgery and Anesthesia; and Council on Cardiovascular and Stroke Nursing. (2021). Mechanical Complications of Acute Myocardial Infarction: A Scientific Statement From the American Heart Association. Circulation, CIR-0000000000000985.
