45 1

INVITED COMMENTARY-

On "Posterior Ventricular Septa1 Rupture: An Anatomical Reconstruction" Philippe Menasche, M.D., Ph.D.

Repair of acute postinfarct posterior ventricu- lar septal defect (VSD) remains a surgical chal- lenge. Although there is wide agreement that op- eration should be performed early after the onset of symptoms, before systemic organ dysfunc- tion occurs, the optimal surgical technique is still a matter of debate. In this area, major contribu- tions have been made by Daggettl and David.2 The article by Pett and associates brings about a "modified" version of these conventional opera- tions designed to overcome their reportedly ma- jor drawbacks and more specifically targeted at eliminating the risk of residual VSD (which is real) and of systemic thromboembolism (which seems to be less relevant). The technique that they propose basically entails (1) the use of two composite patches (made of glutaraldehyde- treated pericardium backed by a piece of syn- thetic fabric) for closing the septal and parietal wall defects, (2) anchoring of the septal patch by sutures passed across the septum from the left ventricular cavity and reinforced, on the right side, by a Teflon felt strip (and not individual pled- gets), (3) meticulous care brought to the place- ment of sutures in the transition area between the septum and the free wall of the two ventri- cles, and (4) an external patch to cover the zone of infarctectomy. This technique, which has been used in four patients, three of whom sur- vived, provides an opportunity to review some of the basic principles that underlie the successful outcome of this difficult operation.

1. Dr. Pett and his colleagues are probably right in recommending the transinfarct approach pio- neered by Daggett.' Recently, the right atrial ap- proach (which, historically, has been abandoned because of its high rate of failure) has been re- vived on the basis of successful results obtained in three patients.3 Whereas the transatrial ap- proach may be indicated in selected cases (like the high VSDs the exposure of which is not obscured by dense ventricular trabeculae), the

transinfarct ventriculotomy remains the best op- tion in the vast majority of patients.

2. Secure anchoring of the septal patch is a critical issue that can be addressed by different techniques. Dr. Pett and associates have used transseptal stitches, which can be of concern be- cause of the friability of the necrotic septum. We therefore prefer the alternate option consisting of excluding the defect by suturing a large patch to the "normal" septal endocardium, as far as pos- sible from the margins of the nonviable area (the base of the patch being anchored directly to the fibrous annulus of the mitral valve). Whereas the authors advocate the use of composite patches, we have been satisfied with a single piece of fresh autologous pericardium that is readily avail- able, easy to handle, and inexpensive. This patch can be sewn with a continuous 4-0 or 5-0 poly- propylene running suture, which is time-saving. This latter consideration is important in these crit- ically ill patients who may require an additional coronary artery bypass graft in addition to an al- ready complex repair. Secure anchoring of the patch can eventually be reinforced by the appli- cation of fibrin glue in the space between the in- ner surface of the patch and the remnants of the necrotic septum. The authors appropriately point out that inaccurate placement of the transition stitches can result in a residual VSD and, from this standpoint, their description of how they deal with this problem is particularly helpful. The sep- tal patch can then be used to exclude the in- farcted myocardium, as recommended by David,2 in which case the lateral side of the patch is su- tured to the posterior wall of the left ventricle by full-thickness stitches buttressed on Teflon felt or pericardial strips applied onto the epicardial sur- face of this wall. Alternatively, the free edge of the septal patch can exit through the ventriculo- tomy and a linear opening made on the second patch used for repairing the parietal wall defect. This outer portion of the septal patch is then sand-

452 MENASCH~ INVITED COMMENTARY

J CARD SURG 1998;13:451-452

wiched by U stitches passing through the parietal patch, the ventricular edges, and the free edge of the septal patch (the excess of which is subse- quently trimmed away). We have found this tech- nique, which has been successfully described by da Silva and coworkers4 for repair of anterior VSDs, to be equally effective in cases of posteri- orly located septal ruptures. Whether anchoring of the septal patch, as described by Dr. Pett and associates, better maintains left ventricular geo- metry remains elusive since the authors do not unfortunately, provide postoperative echocardio- graphic data that would have allowed more accu- rate assessment of how their technique ulti- mately affects cardiac kinetics.

3. Although primary closure of the ventricu- lotomy has been successfully used by David,3 placement of an external patch is probably, in most cases, the safer way of avoiding undue tension on sutures and, consequently, of reduc- ing the risk of postrepair bleeding. We agree with Dr. Pett that this patch should overlay the entire infarcted area although w e prefer not to use interrupted transventricular full-thickness stitches, as they recommend, but rather a con- tinuous 5-0 or 6-0 polypropylene running suture anchoring the peripheral border of the patch to the epicardial layer of the surrounding healthy myocardium.

The multiplicity of techniques that have been described for repairing postinfarct posterior VSDs provides compelling evidence that none are en- tirely satisfactory. Dr. Pett and his colleagues should be complimented for their comprehensive analysis of the pitfalls associated with conven- tional procedures and the subsequent design of an innovative technique. Some features of their operation can possibly be simplified but, overall, its meticulous description contains many techni- cal considerations that should be helpful to the cardiac surgeon who, alone and at night, has to face this difficult lesion.

1

REFERENCES

Daggett WM: Surgical technique for early repair of posterior ventricular septal rupture. J Thorac Car- diovasc Surg 1982;84:306-12.

2. David TE, Dale L, Sun Z: Postinfarction ventricular septal rupture: Repair by endocardial patch with infarct exclusion. J Thorac Cardiovasc Surg 1995;

3. Chan BBK, Nolan SP, Kron IL: Transatrial approach to posterior postinfarct ventricular septal defects. Ann Thorac Surg 1996;62:903-904.

4. da Silva JP, Cascudo, MM, Baumgratz JF, et al: Postinfarction ventricular septal defect. An effica- cious technique for early surgical repair. J Thorac Cardiovasc Surg 1989;97:86-89.

110:1315-1322.