Surgical Treatment of Mechanical Complications of MI - VSD, LV Free Wall Rupture, Papillary Muscle Rupture Flashcards
Describe the pathophysiology of heart failure in an AMI associated VSD (adult).
L-R shunt -> RV overload and failure -> inc flow through pulm circulation -> secondary overload of L heart -> L heart failure -> SVR increase -> increased L-R shunt -> L heart cannot maintain systolic pressure -> L-R shunt declines as pressure equalizes
What populations/risk factors are associated with AMI VSD?
females, older age, CKD, CHF, cardiogenic shock, incomplete coronary revascularization, absence of prior MI (lack of collateralization)
What are physical exam findings of AMI assd VSR (VSD)? What do you need for definitive diagnosis?
S3 gallop, palpable parasternal thrill, and a harsh holosystolic murmur centered at the lower left sternal border with radiation throughout the precordium; plus heart failure signs, cardiogenic shock, chest pain, SoB.
Definitive diagnosis: TTE w/ color doppler - flow across the septum and a drop-out of the signal in 2-dimensional imaging of the septum in a 4-chamber view. LV may be hyperdynamic if it does not already have significant areas of infarcted tissue.
What are the principles of management for AMI assd VSR?
Surgery is the mainstay of treatment. Rushing to the OR is associated with higher mortality.
Before then - stabilize and optimize. Assd w/ improved outcomes following surgical repair.
Achieve this with afterload reducing mechanical circulatory support (IABP) and pharmacologic afterload reduction to reduce the L to R shunting that causes the pathology. A balance with diuresis to reduce overload on a heart at the brink of the starling curve may help.
Careful inotropic support if more forward flow is needed, knowing that this will increase the shunt.
What is the mortality in VSR (2/2 AMI) treated exclusively w/ med mgmt?
24% in the first 24 hours, 46% at 1 week, and 67% to 82% at 2 months.
Operative repair of postinfarction VSR still carries high operative mortality. What is the mortality?
31% to 65%
Describe the Daggett repair of VSR.
The Daggett repair of ventricular septal rupture involves infarctectomy with wide excision of the infarcted tissue and closure of the septal defect and the ventriculotomy with prosthetic patches. Variations include a single-patch technique in which the septal defect and the ventriculotomy are closed with a single patch or multiple patches in several layers with fibrin glue.
Describe the David technique for VSR. Compare it with the Daggett procedure.
exclusion of the infarcted myocardial muscle and ventricular septal defect with an endocardial patch; the David technique has demonstrated superior short- and long-term survival, despite the Daggett procedure being less technically demanding and having a shorter cross-clamp time with a smaller patch and shorter suture line
Should CABG be added to VSR repair?
Not defined. Studies support both benefit and no-benefit in short and long-term outcomes. There are no RCTs.
Are there other procedural options for VSR closure?
Perc Amplatzer device can work to reduce L to R shunt in pts w/ smaller defects and not eccentrically located. Location near the tricuspid/septal leaflet complicate Amplatzer seating. The serpiginous path of the tear can also affect passing a wire.
