Post MI Ventricular Septal Defects Nick Tehrani, MD.
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Post MI Ventricular Septal Defects
Nick Tehrani, MD
Overview
VSD Complicates 1-2% of cases of acute myocardial infarction.First successful correction reported by Cooley in 1957.
Overview
High mortality despite various improvements in therapy
30 day mortality- 74%1 year mortality- 78%
GUSTO analysis, Crenshaw et al,
Circ. 1/2000
Overview
Relative Improvement in survival due to
Earlier diagnosisEarlier flow restoration More aggressive surgical intervention
Overview
Incidence declining due to:
Earlier restoration of flow, preventing transmural MIMore aggressive BP control post MI
Overview
Predictors of VSDAdvanced age,Anterior location of infarction,Female sex,No history of smoking
Per GUSTO analysis
Thrombolysis after 12 hours also suggested as a predisposing factor.
Overview
Average time to rupture2-4 days
Range: few hours 2 weeks
Time course may be accelerated by thrombolysis, possible related to intramyocardial hemorrhage
Overview
Coronary anatomy and VSD
Post MI VSDs more commonly associated with 100% occlusion of the infarct related arteryThis was observed in all of our patients
Anatomy of VSDs
Two types of VSD
Simple: through and through defect usually located anteriorlyComplex: serpentiginous dissection tract remote from the primary septal defect- most commonly an inferior VSD
Patient BG had such a presentation
Transesophageal Echocardiogram of Complex VSD
Angiography
Anatomy of VSDs
Antro-apical septal rupture
Comprise approximately 60-80% of casesLAD occlusion is always the culprit
Anatomy of VSDs
Posterior septal ruptureApproximately 20-40% of casesOcclusion of
Dominant RCA => extensive RV infarctionDominant LCX (Less common), RV mostly spared
Anatomy of VSDs
Multiple defects (5-11% of cases)
Secondary to infarct extensionEvolve within days of each other
Anatomy of VSDs
Our series
Antro-apical septumThree of four cases
Posterior septum One of four cases
Pathophysiology
Antero-apical septal rupture
TamponadeSecondary RV failiure due to acute volume overload
Pathophysiology
Posterior septal ruptureCommonly complicated by MRShunt reversal due to elevated RVEDP
Diagnosis
Loud/harsh pansystolic murmur
Within the first week post AMIBest heard at Lt. Lower sternal borderLess loud at the apexAssociated with a palpable thrillDepending on the location, may radiate to the axilla mimicking MR
Diagnosis
Up to 50% of patients experience chest pain associated with the development of murmur
CHF and shock often associated with the development of murmur
Diagnosis
Color Flow Doppler
100% sensitive and specific in differentiating VSD from acute MRSite of septal rupture correctly identified in 41 of 42 patientsOne of our 4 patients had had a negative TTE earlier in the day, and no apparent homodynamic changes prior to the catheterization later that day
Smyllie et. Al. 1990 JACC
Diagnosis
Earlier diagnosis and surgical intervention, may be due to greater availability of Echocardiography at peripheral centers.
Diagnosis
Need for cardiac catheterization2/3 of the patients have multivessel coronary artery diseaseDecreased operative mortality and improved late survival has been shown in patients with multivessel diseaseCardiogenic shock not a deterrent to Cath
=> Coronary angiography should be performed
Diagnosis
Pre-Operative Management
Hemodynamic stabilization so as to minimize peripheral organ compromise
Reduce Systemic vascular resistance, and thus, the left-to-right shuntMaintain or improve coronary artery blood flowMaintain cardiac output and arterial pressure to ensure peripheral organ perfusion
=> IABP
Timing of Surgery
Controversial (in the past)Non-randomized studies showing:
Early repair, 40% - 50% mortalityLate repair (past 3 weeks), 10% mortality
=>
Aggressive Medical management aimed at delaying surgical intervention
Timing of Surgery
Short-coming of the argumentPatients with less sever hemodynamic compromise, more likely to survive the acute phase without need for prompt
surgery:
Lower pre-op risk =>Better outcome
Timing of Surgery
Short-coming of the argumentPatients with greater hemodynamic compromise, and more severe insult:
Higher pre-op risk =>Worse outcome
Timing of Surgery
Surgery should be performed soon after diagnosis in most patientsPatients is cardiogenic shock should be operated on immediately after anigographyHemodynamically stable patients should have surgery on an urgent basis
Operative Technique
Classical approach to antero-septal rupture
Infarctectomy, andReconstruction of the ventricular septum with Dacron patches
Operative Technique
Classical approach to infro-posterior rupture
Infarctectomy, andReconstruction of infroposterior VSD,
ReconstructionReconstruction free wall with Dacron patches.
Outcome
In a review of 139 cases reported in the literature prior to 1977
Six month survival without surgical intervention was less than 10%.
Kirklin, Churchill Livingston 1993
Outcome
Predictors of early mortality per multivariable logistic regression analysis in a series of 22 patients
DMElevated RA pressure (RV involvement/IMI)Absence of intraoperative IABP
Outcome
Predictors of early mortality per GUSTO analysis
Advanced ageInferior location of MI
Outcome
In patients with cardiogenic shock mortality reported to be the highest
Posterior VSD (IMI) is another factor strongly associated with poor surgical outcome due to
Difficulty of exposure, and Frequent concomitant infarction of the postero-medial papillary muscle
Compilation from 6 series from the late 80s
Outcome
David, in a series of 44 patients reported no difference between mortality rates for the posterior and anterior VSD using the
Exclusion technique
Exclusion Technique
Exclusion techniqueLV excluded from the infarcted muscle using a bovine pericardial patch sutured to the healthy peri-infarct endocardiumNo infarctectomy is performed RV is undisturbed
Better RV function preservationMay help support the posteromedial papillary muscle
Exclusion technique
Exclusion technique
Outcome
Residual Lt. Rt. shunt
Reported in up to 28% of survivorsAssociated with high mortalityIntra-operative TEE useful in early detection and correction if deemed necessarySeen in one of our patients.
Patient was treated medically
Residual VSD
Post-Op state
DialysisCommonly required in patients in shockNot required by either of our two survivors
Prolonged ventilatory supportResidual or recurrent VSD
Reoperation may be necessary depending on the shunt size and hemodynamics
Clinical Profile of our Patients
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