VENTRICULAR SEPTAL DEFECT WITH AORTIC INSUFFICIENCY

Surgical correction of ventricular septal defect with aortic regurgitation in a dog

An 8-month-old entire Miniature Dachshund, weighing 4.2 kg, was presented for examination following delvelopment of a cough. Ventricular septal defect had been diagnosed tentatively in its infancy on the basis of a cardiac murmur detected by auscultation and echocardiography. Echocardiography using a B mode right parasternal long-axis view showed a defect at the atrioventricular junction and a thickened cusp of the aortic valve prolapsing into the defect. Colour-flow Doppler showed shunt blood flow across the defect at the level of the atrioventricular junction, from left to right. The sinus of Valsalva was dilated, with turbulent blood flow. Aortic regurgitation was also observed. Cardiac catheterisation studies confirmed the diagnosis of a supracristal ventricular septal defect with aortic regurgitation. Despite medication with digoxin, enalapril and aminophylin, started from the first admission, left ventricular internal dimensions gradually increased, and fractional shortening of the left ventricle gradually decreased. Surgery, with the aid of extracorporeal circulation, to close the ventricular septal defect, was performed 1 year after the initial examination. The aortic valve was left untreated. Postoperatively, the systolic murmur disappeared. Shunt flow from the left to the right ventricle was no longer observed on echocardiography, however there was still a small amount of aortic regurgitation during diastole visualised with colour-flow Doppler echocardiography. The prolapse of the cusp of the aortic valve on B-mode echocardiography was no longer observed and thickening of the cusp had not progressed. Left ventricular function measurement using M mode echocardiography showed a reduced left ventricular volume overload with reduced left ventricular internal dimensions and increased fractional shortening. The cough was relieved and no follow-up medication was scheduled. Early surgical closure of the ventricular septal defect improved the patient's condition and controlled prolapse and thickening of the aortic valve.

Surgical treatment of supracristal type of ventricular septal defect

Surgically treated ventricular septal defect (VSD) was of supracristal type in 120 of 389 Chinese patients; 93 of the 120 were younger than 15 years. Concomitant aortic anomalies were present in 58 of the patients (regurgitation in 23 and cusp prolapse in 35). Corresponding figures among the 93 patients of the under-15 group were 40 (9 + 31). Direct suture or patch closure of the supracristal VSD and replacement or plication of anomalous aortic valves were the methods used. The results of direct closure were equal to those of patch closure. One patient died of subacute bacterial endocarditis, which had been present preoperatively. There were no other deaths. The postoperative observation period was 6 months to 7 years. As the incidence of associated valvulopathy increases with patient age, early operation for supracristal VSD, regardless of shunt volume, is advocated.

Usefulness of electromagnetic flowmetry in intraoperative evaluation of aortic regurgitation associated with ventricular septal defect

In 38 patients with aortic regurgitation (AR) associated with ventricular septal defect (VSD), indications for aortic valvuloplasty (AVP) or aortic valve replacement (AVR) were investigated by assessing AR ratio, which was measured by electromagnetic flowmetry of the ascending aorta during the operation. Residual AR was evaluated by auscultation postoperatively. Patients were assigned to group A if they underwent VSD closure alone and to group B if they underwent AVP in addition to VSD closure; patients who had no postoperative AR were assigned to group I and those with persistence of AR to group II. Thus, the patients were separated into 4 subgroups; A-I (9 patients), A-II (5 patients), B-I (20 patients) and B-II (4 patients). In subgroup A-I, mean AR ratio decreased from 9% to 7% postoperatively, in A-II from 19% to 16% (p less than 0.1), in B-I from 36% to 9% (p less than 0.01) and in B-II from 44% to 20% (p less than 0.05). An AR ratio of more than 25% should be regarded as an absolute indication for AVP or AVR. If the AR ratio is between 20 and 25%, the indication of AVP is determined by inspection of the aortic valve. A good correlation was found between AR ratio and the AR rate determined by the aortic angiographic findings (Sellers classification): grade I AR corresponded to an AR ratio of 5 to 15%, grade II to 20 to 35%, grade III to 25 to 50% and grade IV to 45% or higher (r = 0.87, p less than 0.01).

Pathogenetic mechanisms of prolapsing aortic valve and aortic regurgitation associated with ventricular septal defect. Anatomical, angiographic, and surgical considerations

The developmental mechanisms of prolapse and regurgitation of the aortic valve which complicate ventricular septal defect (VSD) were investigated from the anatomical, angiographic, and surgical viewpoints on the basis of autopsied heart specimens, preoperative thoracic aortography, and surgical records.

Two major, conceptually distinct but functionally interdependent factors contribute to the aortic valve's prolapse into the VSD. The major feature of the first category is the lack of anatomical support for the valve. In subpulmonary VSD, a regional defect of the conal septal musculature which supports a section of the right coronary sinus and the annulus was observed. In infracristal VSD, a deficiency of the sinus of Valsalva was noted.

The hemodynamic effects, which actually produce prolapse of the anatomically unsupported valve into the VSD, is the second contributing factor. The left-to-right shunt of blood through the VSD during the early systolic phase pulls the sagging aortic valve into the defect. The distinctive feature of the second category is that prolapse of the anatomically unsupported valve is produced by hemodynamic effects. Diastolic aortic pressure does not appear to contribute greatly to bulging of the aortic valve into the right ventricular cavity. However, in the diastolic phase, the closed valve is subject to intra-aortic pressure, causing the free margin of the prolapsed cusp to hang down, to gradually become elongated, and finally to separate from the free margin of the other two cusps, and thus be rendered incompetent.

Ventricular septal defect associated with aortic insufficiency: anatomic classification and method of operation

Thirty-five consecutive patients with ventricular septal defect (VSD) associated with aortic insufficiency (AI) who underwent corrective surgery are presented. There were seven operative and three late deaths among the patients operated upon before 1968. No death, however, was encountered among the most recent 18 consecutive patients. The VSD was closed directly in 14 patients and with a Teflon patch in 21. The aortic valve was repaired in 16 patients, replaced in eight, and no interference was indicated in 11.

They were classified from the surgical viewpoint according to the location of the VSD, the anatomic type of the right ventricular outflow tract, and the severity of the aortic herniation as follows: type Ia, supracristal VSD and AI without aortic cusp herniation; type lb, supracristal VSD and AI with aortic cusp herniation and conal muscular rim beneath the pulmonic valve; type Ic, supracristal VSD and AI with aortic cusp herniation without conal muscular rim beneath the pulmonic valve; type IIa, infracristal VSD and AI without aortic cusp herniation; type IIb, infracristal VSD and AI with aortic cusp herniation; type III, infracristal VSD and AI with infundibular pulmonic stenosis (PS); type IV, supracristal VSD and AI with infundibular PS.

In type Ia and IIa, VSD was closed directly and the aortic valve was replaced. In most of type Ib, VSD was closed directly and no direct procedure was performed upon the aortic valve. In most of type Ic, VSD was closed with a Teflon patch and the aortic valve was repaired. In type IIb, VSD was closed with a Teflon patch and the procedure upon the aortic valve was not uniform. In type III, VSD was closed with a Teflon patch and the aortic valve was repaired in most of them. In type IV, VSD was closed with a Teflon patch and no direct procedure was performed upon the aortic valve.

The basic policy for repair of this association of anomalies is selected according to the above mentioned anatomic classification.

Aortic regurgitation with ventricular septal defect. Surgical management and clinical features

Twenty patients with ventricular septal defect and aortic regurgitation had surgical correction using cardiopulmonary bypass. Direct suture of the ventricular defect through the aorta and repair or replacement of the aortic valve were performed. Homograft replacement of the aortic valve was preferred to repair and was associated with less aortic regurgitation after operation. There were one operative death and one late death due to aortic regurgitation. Follow-up for 1 to 6 years showed that 17 of the 18 survivors have had a satisfactory result.

Ventricular Septal Defect with Aortic Regurgitation

Thirty-four patients with ventricular septal defect and aortic regurgitation, representing less than 5 per cent of our patients with ventricular septal defect, are discussed.

A loud, systolic murmur, characteristic of ventricular septal defect, is noted during infancy, whereas evidences of aortic regurgitation (protodiastolic murmur and wide pulse pressure) does not usually appear until sometime between 2 and 10 years of age.

Clinical and catheterization data indicate that the principal hemodynamic load is aortic regurgitation, whereas the ventricular septal defect does not usually result in a large pulmonary blood flow or high pulmonary arterial pressure. In about 50 per cent of the patients, a significant pressure gradient across the right ventricular outflow tract exists.

Detailed pathologic studies indicate that the ventricular septal defects are high and anterior and encroach to a greater or lesser degree on the membranous bulbar septum. The right coronary cusp is the one most severely involved, and, by its prolapse, causes aortic regurgitation; the noncoronary cusp is always less severely affected. The anatomic basis of the pressure gradient observed across the right ventricular outflow tract is not always clear.