EComment. An oval-shaped unidirectional check-valved patch for treating ventricular septal defects

Abstract

We read with great interest the manuscript of Talwar et al. [1], in which the authors presented their experience of ventricular septal defect (VSD) closure with a unidirectional valved patch in patients with severe pulmonary hypertension. We would like to comment on a few points of the authors' paper. As a referral centre for the region, we receive similar patients, i.e. who are still operable but are high risk candidates for VSD closure due to increased pulmonary vascular resistance, and we use a similar technique. All patients receive detailed echocardiographic examinations and cardiac catheterization studies preoperatively. As soon as the patients are prepared for operation, a transoesophageal echocardiography probe is inserted. The dimensions, shape, and boundaries of the VSD are once again verified. A surgeon prepares the valved patch while the other starts the operation so that the delay during cardiac arrest is minimized. A hole is created on a square Dacron patch with an aortic punch. Another ‘U’ shaped Dacron patch is sewn on this patch 4-5 mm away from the margins of the fenestration. The open end of the ‘U’ is left unsewn. The exact size of the patch is adjusted when the VSD is explored. Most often, although three-dimensional, the VSDs are round or oval. An oval-shaped patch has smooth edges and is also easy for VSD closure. Thus we usually trim the reconstructed patch into a round or oval-shape. The authors used a folded, fenestrated patch [1]. Although it seems easier and faster to construct such a patch, size adjustment, if needed, does not seem easy, since trimming may encounter the suture lines. Moreover, since the fenestration is directed at the left ventricular apex, the sharp margin of the patch may be faced towards the tricuspid or semilunar valves, which may perhaps have valvular consequences. Additionally, when open, the valve of the patch may lead to outflow tract obstruction and leaflet damage in the long term. Another point is regarding the postoperative management of the patients. Authors stated that none of their patients had required nitric oxide during the intensive care unit stay [1]. In our practice we routinely administer inhaled nitric oxide to facilitate postoperative recovery in pulmonary hypertensive patients. In the manuscript, mean systemic saturation was 96.3 ± 4% (87% being the lowest) and 18% of the patients had episodes of systemic desaturation indicating a right-to-left shunt due to increased pulmonary pressure [1]. We believe that nitric oxide would have been very beneficial, especially in those patients. We would like to congratulate the authors for their successful management strategy of such a high risk patient group and for stressing once again the importance of unidirectional valved patches in treating patients with increased pulmonary vascular resistance.