Mechanical Complications of Acute Myocardial Infarction

Coronary artery disease (CAD) is a major cause of mortality and morbidity worldwide. In the United States cardiovascular disease is the leading cause of death in people older than 65 years. In the current era, a complete recovery after an acute myocardial infarction (AMI) has become the norm. Unfortunately, however, the mortality for some patients remains high. In particular, patients with cardiogenic shock after an AMI have less than a 50% chance of surviving their hospital stay.

Cardiogenic shock in AMI may result from ventricular dysfunction or it may result from mechanical complications requiring emergency surgical treatment; these include: papillary muscle rupture, ventricular free wall rupture and ventricular septal defect.

With the advent of percutaneous coronary intervention (PCI), there has been a significant drop in the incidence of post-infarction mechanical complications.The incidence of mechanical complications after acute ST elevation MI (STEMI) in the APEX-MI trial, where primary PCI was the reperfusion strategy, was 0.9%.

Although the incidence has decreased in the last decades, mortality in patients who develop these complications after AMI still remains very high. Mechanical complications must be carefully searched for in any patient with an acute coronary syndrome and signs of cardiogenic shock. The diagnosis, or even the suspicion, requires urgent surgical referral and in most cases necessitates emergency surgery.

The management of patients with postinfarction mechanical complications requires the consideration of several factors: (i) the extremely poor prognosis without surgical treatment; (ii) the higher mortality risk associated with emergency surgery; (iii) the potential rapid deterioration of initially stable patients.

Data from the Society of Thoracic Surgeons National Database demonstrated an average 43% in-hospital/30-day mortality for surgical treatment of ventricular septal defect. Reports on outcomes in large free wall rupture and papillary muscle rupture cohorts are scarce; based on available data, in-hospital mortality after surgery is around 20-25% for acute mitral regurgitation and 12-36% for ventricular free wall rupture.

In conclusion, because of the rarity of these post-AMI mechanical complications, the optimal evidence-based therapeutic strategies remain controversial, and little is know on the early clinical results and late follow-up.

Owing to the paucity and limitation of available data, investigations and analysis are required to help clinicians make an early diagnosis of these devastating complications, and offer to patients the appropriate surgical treatment. "Mechanical complications of acute myocardial infarction: an international multicenter cohort study" (Caution Study 1) is a retrospective, international multicenter clinical trial aimed at evaluating the survival, postoperative outcome and quality of life of patients underwent cardiac surgery for post-infarction mechanical complications.

Inclusion criteria

• Patients ≥ 18 years old;
• Patients who received surgical treatment for mechanical complications of AMI from January 2001 to December 2018.

Exclusion criteria

• Patients who underwent medical/conservative management for post-AMI mechanical complications or cardiac surgery procedures (for example: left ventricular free wall rupture repair) not related with post-AMI complications (for example: traumatic ventricular wall rupture).