Repair of posterior ventricular septal rupture by right atrial approach

Ventricular septal rupture (VSR) is a serious complication that may occur after myocardial infarction (MI).^[1] If left untreated, it will lead to high morbidity and mortality. Although several surgical interventions have been developed, mortality and complications associated with surgical management are still high, especially in terms of transventricular approaches.^[2]

Among these patients, anterior VSR (66%–78%) and posterior VSR accounted for about 17%–22%.^[3] Compared with surgical repair of anterior VSR, the operative mortality of posterior VSR is higher.^[4] In this study, we report the case of a patient with posterior VSR that was repaired via the right atrial approach.

A 52-year-old male complained of chest tightness for more than half a year after exercise, aggravated for two weeks, and had a history of hypertension. On admission, systolic murmur could be heard between the third and fourth intercostals of the left margin of the sternum. Coronary angiography showed left anterior descending artery (LAD) stenosis (85%), right coronary artery (RCA) stenosis (70%), and distal occlusion of the left circumflex artery branch (Figure 1). Echocardiography showed that interventricular septal perforation was accompanied by left-to-right shunt and mild to moderate mitral regurgitation (Figure 2). It was diagnosed as coronary heart disease and interventricular septal perforation. The patient underwent VSR repair and coronary artery bypass grafting twenty-one days after admission.

Figure  1.  Coronary angiography showed distal occlusion of left circumflex artery branch.

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Figure  2.  Echocardiography showed that interventricular septal perforation was accompanied by left-to-right shunt and mild to moderate mitral regurgitation.

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The median sternal incision was taken, the pericardium was cut and suspended, and part of the pericardium was reserved. It was found that the left atrium and left ventricle were significantly enlarged, and the size of the right atrium and right ventricle was basically normal. Routine establishment of cardiopulmonary bypass and occlusion of the superior and inferior vena cava, longitudinal incision of the right atrium, detection of posterior ventricular septal defect, about the size of 2 cm × 2 cm (Figure 3A). The 2-0Ethibond suture was used to insert the needle from the distance of the defect, gently pulled up the silk thread after each injection to expose the position of the next needle, and placed the gasket on the normal tissue of the left ventricle about 1–2 cm away from the defect, a total of eight stitches (Figure 3B). Then took the bovine pericardial patch with the smooth surface facing the left ventricle and carefully followed the patch to the perforation (Figure 3C). Due to the lack of marginal tissue near the posterior septum, the gasket was placed outside the ventricle into the needle (Figure 3D). The edge of the bovine pericardial patch was continuously sutured to the normal interventricular septum tissue around the suture with 4-0Prolene suture (Figure 3E). After exposing the target area of LAD, the coronary artery was cut with a sharp knife and enlarged with anterior scissors and back scissors respectively, and the 1.5 mm shunt plug was placed. The great saphenous vein was anastomosed to the target area of LAD with 8-0Prolene suture. RCA was exposed and the proximal end of the great saphenous vein was anastomosed with RCA with 8-0Prolene suture. The perfusion cannula was removed and the distal end of the great saphenous vein was anastomosed to the aortic perforation with two 6-0Prolene sutures. Immediately after operation, esophageal echocardiography showed that there was no shunt flow in the repair of interventricular septum. The patient was successfully removed from cardiopulmonary bypass and transferred to the intensive care unit under mechanical ventilation.

Figure  3.  Major surgical procedures.

(A): The size of interventricular septal perforation is about 2 cm × 2 cm; (B): gently pull up the silk thread after each injection to expose the position of the next needle; (C): the smooth surface of the bovine pericardial patch faces the left ventricle; (D): the gasket was placed outside the ventricle into the needle; (E): the edge of the patch was continuously sutured to the normal interventricular septum tissue; and (F): two layers of sutures firmly cover the patch at the ventricular septal rupture.

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On the first day after stable circulatory and spontaneous respiratory function, extubation was performed, and postoperative echocardiography showed that there was no residual shunt in the interventricular septum and ventricular muscle activity was normal. The patient was transferred to the general ward the second day after operation and was discharged smoothly on the ninth day.

VSR is a rare but serious complication that can occur after MI. With the development of percutaneous coronary intervention, the incidence of post-infarction VSR has decreased; however, the mortality rate is still very high. In general, most surgeons operate through left ventriculotomy or through the free wall of infarction. However, in the case of posterior VSR, it is difficult to enter through the free wall of left ventricular incision or infarction.^[5] Exclusion of infarction by left ventriculotomy is an additional injury to already unstable myocardium.^[2] There are several problems in ventriculotomy: (1) remodeling after MI and making a large incision on the free wall of the ventricle can affect postoperative low cardiac function and ventricular arrhythmia; and (2) larger sutures and tight closure of the ventricles also reduce the remaining ventricular volume and worsen the diastolic function of the heart.^[6] Also, there was a technical obstacle of difficult dissection with uneasy access to the previous left ventriculotomy in this case, which was complicated by a patent coronary artery bypass graft.

To minimize these problems, Filgueira, et al.^[7] reported an alternative surgical approach using right atriotomy in 1986. The right atrial approach avoids these problems and eliminates the need for ventriculotomy and re-suture so that viable myocardium and cardiac function can be preserved. In VSR repair, sutures must be placed at the fragile edge of the infarcted interventricular septum, and sometimes large patches are needed to cover the defects. Suturing from the right atrium to the deep end of the interventricular septum is complicated.^[8] The major disadvantage of the right atrial approach is the need to incise the septal leaflets of the tricuspid valve to expose the defect.^[9]

In this case, when stitching the bovine pericardial patch, we used an improved technique, gently pull up the silk thread after the first needle, so that the next needle area can be well exposed, which is helpful to accurately locate the patch to the perforation, as a result, the line of sight exposed to the defect through the right atrium is unobstructed, and the original structure of the tricuspid valve is completely preserved. And then the edge of the patch is continuously sutured to normal myocardial tissue, so that the double-layer suture structure can greatly enhance the stability of the patch and prevent blood flow from seeping out from the edge of the patch (Figure 3F).

The best management of VSR is still a controversial topic, considering factors such as early surgery and delayed surgery.^[1] After a waiting period of 4–6 weeks, the necrotic myocardium can be remodeled by fibrosis, and the tensile strength is high enough to support the insertion of the defect area.^[10] This can improve the prognosis of patients who survive the waiting period.^[11] However, patients with hemodynamic instability should be operated as soon as possible.^[1]

In this case, the patient underwent surgery three weeks after diagnosis. Delaying surgery can keep patients stable for a period of time and improve their medical conditions before undergoing surgery. This includes the management of heart failure, the optimization of hemodynamic parameters and the correction of electrolyte imbalance. By improving the overall physiological status of patients, delayed operation reduces the risk of perioperative complications and increases the chance of successful operation.

In conclusion, the right atrial approach is very useful for the treatment of posterior VSR after MI, which can better expose the surgical visual field, ensure stable suture, and retain the structure and function of the left ventricle.