Modified Konno-Rastan procedure for subaortic stenosis: indications, operative techniques, and results

Aortic valve replacement using Konno procedure for prior Yasui procedure

A 2-year-old girl underwent conversion to the Konno procedure by removing the Damus-Kaye-Stansel anastomosis after the neonatal Yasui procedure for an interrupted aortic arch with left ventricular outflow tract stenosis. Her postoperative course was uneventful. However, left ventricular outflow tract restenosis occurred due to narrowed ventricular septal defect and moderate neoaortic regurgitation from the old pulmonary valve. The Konno procedure was performed by removing the Damus-Kaye-Stansel anastomosis for left ventricular outflow tract restenosis and neoaortic regurgitation and performing right ventricular outflow tract reconstruction and ventricular septal defect closure. Left ventricular outflow tract restenosis was not observed.

Paediatric subaortic stenosis: long-term outcome and risk factors for reoperation

 

OBJECTIVES

Surgical repair of subaortic stenosis (SAS) is associated with a substantial reoperation risk. We aimed to identify risk factors for reintervention in relation to discrete and tunnel-type SAS morphology.

METHODS

Single-centre retrospective study of paediatric SAS diagnosed between 1992 and 2017. Multivariable Cox regression analysis was performed to identify reintervention risk factors.

RESULTS

Eighty-five children [median age 2.5 (0.7-6.5) years at diagnosis] with a median follow-up of 10.1 (5.5-16.4) years were included. Surgery was executed in 83% (n = 71). Freedom from reoperation was 88 ± 5% at 5 years and 82 ± 6% at 10 years for discrete SAS, compared to, respectively, 33 ± 16% and 17 ± 14% for tunnel-type SAS (log-rank P < 0.001). Independent risk factors for reintervention were a postoperative gradient >20 mmHg [hazard ratio (HR) 6.56, 95% confidence interval (CI) 1.41-24.1; P = 0.005], tunnel-type SAS (HR 7.46, 95% CI 2.48-22.49; P < 0.001), aortic annulus z-score <-2 (HR 11.07, 95% CI 3.03-40.47; P < 0.001) and age at intervention <2 years (HR 3.24, 95% CI 1.09-9.86; P = 0.035). Addition of septal myectomy at initial intervention was not associated with lesser reintervention. Fourteen children with a lower left ventricular outflow tract (LVOT) gradient (P < 0.001) and older age at diagnosis (P = 0.024) were followed expectatively.

CONCLUSIONS

Children with SAS remain at risk for reintervention, despite initially effective LVOT relief. Regardless of SAS morphology, age <2 years at first intervention, a postoperative gradient >20 mmHg and presence of a hypoplastic aortic annulus are independent risk factors for reintervention. More extensive LVOT surgery might be considered at an earlier stage in these children. SAS presenting in older children with a low LVOT gradient at diagnosis shows little progression, justifying an expectative approach.

Management of Complex Left Ventricular Outflow Tract Obstruction: A Comparison of Konno and Modified Konno Techniques

Management of complex left ventricular outflow tract obstruction (LVOTO) can be achieved with a Konno or Modified Konno procedure to enlarge the LVOT. We hypothesized that patients who undergo a Modified Konno procedure would have a higher rate of LVOT re-intervention compared to the Konno procedure. Patients who underwent a Konno or Modified Konno procedure for LVOTO at a single tertiary care center between 1990 and 2014 were retrospectively reviewed. The primary outcome was LVOT re-intervention post-discharge from index Konno or Modified Konno procedure. Cox regression and Kaplan-Meier estimates were used for time-to-event analysis of LVOT re-interventions, any unplanned re-interventions, and transplant-free survival. The study included 122 patients: 51 (41.8%) in the Konno group and 71 (58.2%) in the Modified Konno group. Median age at surgery was 8.2 (IQR 3-16) years in the Konno group and 3.9 (IQR 1.5-11) years in the Modified Konno group. Multiple left heart lesions were less prevalent in Modified Konno patients. There were 36 (29.5%) patients with LVOT re-interventions: 8 (16%) in the Konno group and 28 (39.4%) in the Modified Konno group (p = 0.01). Transplant-free survival at five years was 87.2% for the Konno group and 93.5% for the Modified Konno group. A higher rate of LVOT re-intervention was found in the Modified Konno group although the Konno and Modified Konno techniques were applied to different patient populations. This finding suggests that careful preoperative decision-making can direct therapy appropriately and that fundamental diagnosis affects procedure choice.

Biventricular Repair of Double Outlet Right Ventricle: Preoperative Echocardiography and Surgical Outcomes

OBJECTIVE

To discuss the key anatomic features of double outlet right ventricle (DORV) assessed by preoperative echocardiography among patients treated with different types of biventricular repair.

METHODS

Surgical and echocardiographic databases were queried to identify patients who had undergone biventricular repair for DORV and had adequate preoperative echocardiographic imaging. All patients underwent pre- and postoperative echocardiography and clinical evaluation following discharge.

RESULTS

Two hundred sixty-two patients with DORV met the inclusion criteria of the study. The patients were divided into two groups-intraventricular tunnel repair (IVR) to the aorta (194 [74%] patients) or to the pulmonary artery with either concomitant arterial switch operation or double-root translocation (68 [26%] patients). Among 68 patients undergoing IVR to the pulmonary artery, 50 patients with transposition of the great arteries (TGA) type of DORV and 7 patients with remote ventricular septal defect (VSD) type underwent IVR plus arterial switch operation and 6 patients with TGA type and 5 patients with remote VSD type underwent IVR plus double-root translocation. There were three hospital deaths and one late death (overall operative mortality: 1.5%).

CONCLUSION

Preoperative echocardiography provided crucial data to estimate the feasibility of intraventricular tunnel creation to either the aorta or the pulmonary artery and to guide the selection of either arterial switch or double-root translocation. Biventricular repair could be achieved with favorable outcomes in most patients with DORV.

Echocardiographic Classification and Surgical Approaches to Double-Outlet Right Ventricle for Great Arteries Arising Almost Exclusively from the Right Ventricle

Selecting an appropriate surgical approach for double-outlet right ventricle (DORV), a complex congenital cardiac malformation with many anatomic variations, is difficult. Therefore, we determined the feasibility of using an echocardiographic classification system, which describes the anatomic variations in more precise terms than the current system does, to determine whether it could help direct surgical plans. Our system includes 8 DORV subtypes, categorized according to 3 factors: the relative positions of the great arteries (normal or abnormal), the relationship between the great arteries and the ventricular septal defect (committed or noncommitted), and the presence or absence of right ventricular outflow tract obstruction (RVOTO). Surgical approaches in 407 patients were based on their DORV subtype, as determined by echocardiography. We found that the optimal surgical management of patients classified as normal/committed/no RVOTO, normal/committed/RVOTO, and abnormal/committed/no RVOTO was, respectively, like that for patients with large ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries without RVOTO. Patients with abnormal/committed/RVOTO anatomy and those with abnormal/noncommitted/RVOTO anatomy underwent intraventricular repair and double-root translocation. For patients with other types of DORV, choosing the appropriate surgical approach and biventricular repair techniques was more complex. We think that our classification system accurately groups DORV patients and enables surgeons to select the best approach for each patient's cardiac anatomy.

Modified Konno operation for diffuse subaortic stenosis

The modified Konno operation is designed to provide relief of diffuse subaortic stenosis, while preserving the native aortic valve. The aorta and the right ventricular infundibulum are opened. The upper part of the subaortic stenosis is incised through the aortic orifice. The conal septum is incised and the septotomy is extended across the stenotic area. The obstructive tissue is removed (mainly from the left-handed rim of the septotomy) and the conal septum is enlarged with a prosthetic patch. The aorta is closed and the right ventricular infundibulum is enlarged. Early and late mortality rates are low. Potential morbidity (complete heart block, residual ventricular septal defect, iatrogenic aortic insufficiency, right ventricular outflow tract obstruction) should be minimized by a careful surgical technique. The modified Konno operation is indicated in patients with diffuse subaortic stenosis and a normal aortic orifice; this includes patients with severe forms of hypertrophic obstructive cardiomyopathy and children with tunnel subaortic stenosis and a normal aortic orifice; the modified Konno procedure provides long-lasting relief of the obstruction. In patients with tunnel stenosis and a borderline-sized aortic annulus, residual obstruction may develop at the valvar level and need reoperation; the modified Konno operation can, however, delay aortic valve replacement.

Fixed subaortic stenosis: a clinical dilemma for clinicians and patients

Subaortic stenosis carries considerable morbidity and mortality. In most cases, patients have an underlying left ventricular outflow tract morphology that promotes turbulence at the outflow tract, which induces the development of subaortic fibromuscular tissue. A subset of patients will progress to develop severe stenosis and aortic regurgitation, but it has been difficult to determine which patients are at risk. While resection of the subaortic tissue improves immediate outcome, many patients have recurrence of both stenosis and regurgitation, questioning the efficacy of surgical intervention in asymptomatic patients. This review article describes the current understanding of the etiology, treatment, and prognosis of subaortic stenosis.

Modified Konno procedure: surgical management of tunnel-like left ventricular outflow tract stenosis

Left ventricular outflow tract stenosis represents 1-2 % of all congenital anomalies. In particular, tunnel-like left ventricular stenosis which is one type of fixed left ventricular outflow stenosis requires aggressive surgery to reduce the left ventricular outflow gradient. The purpose of the modified Konno procedure is to release fixed left ventricular outflow tract stenosis while preserving the native aortic valve and its function. Although the clinical results of the modified Konno procedure are acceptable, it is necessary to precisely understand this procedure and the anatomy of the left ventricular outflow tract in order to avoid complications.

Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: outflow tract obstruction, coarctation of the aorta, tetralogy of Fallot, Ebstein anomaly and Marfan's syndrome

With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. Part II of the guidelines includes recommendations for the care of patients with left ventricular outflow tract obstruction and bicuspid aortic valve disease, coarctation of the aorta, right ventricular outflow tract obstruction, tetralogy of Fallot, Ebstein anomaly and Marfan's syndrome. Topics addressed include genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy risk and follow-up requirements. The complete document consists of four manuscripts that are published online in the present issue of The Canadian Journal of Cardiology. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.

Long-term Outcome and Risk of Heart Block After Surgical Treatment of Subaortic Stenosis

Although mortality following repair of subaortic obstruction is low, aggressive resection may increase morbidity. We sought to evaluate outcomes and risk of atrioventricular heart block (AVB) after subaortic resection in the current era. Simple obstruction was defined as a discrete subaortic membrane and complex as multilevel or diffuse narrowing. Limited resection included membranectomy and limited myomectomy. Aggressive resection included Konno, modified Konno, and Ross. Specified variables were obtained from a chart review. The 185 consecutive patients (1991-2008) ranged in age from 1 day to 21.8 years (5.1 ± 5.1 years) with 2 early and 4 late deaths. Actuarial survival was 97%, 95%, and 95% at 1, 5, and 10 years, respectively. Reoperations were required in 29 of 185 patients (15.7%); 2 required a third operation (1%). Freedom from reoperation in all patients was 97%, 83%, and 73% at 1, 5, and 10 years, respectively. Accessory mitral valve tissue ( P < .001) and age <3 months ( P = .004) predicted the need for reoperation. Transient or permanent high-degree AVB was documented in 33 of 185 patients (17.8%). Complex anatomy ( P = .01) and aggressive resection ( P < .001) increased the risk of acquiring AVB. The AVB was permanent in 21 of 185 (11.4%) patients, and pacemaker implantation was undertaken in 20 of 185 (10.8%) patients. Complex anatomy ( P = .04) and modified Konno procedure ( P = .03) increased the risk of acquiring a pacemaker. Aggressive resection lowered the frequency of recurrence but increased the risk of AVB. When aggressive resection is considered for long-term relief of subaortic obstruction, the risk of reobstruction must be balanced with the risk of AVB and the need for pacemaker implantation.

Correction of discrete subaortic stenosis with abnormal chordae tendineae

The case of a 52-year-old woman with subvalvular aortic stenosis and aortic regurgitation is presented. Mitral regurgitation was associated, due to insertion of two abnormal chordae tendineae at the apex of the anterior papillary muscle and at the free border of the subvalvular membranous annulus. This abnormality displaced the anterior papillary muscle, thus applying a traction at the mitral leaflet. The patient was operated on through a valve-sparing approach, in which the discrete subaortic stenosis was removed through aortotomy and the ectopic chordae were excised. Suture mitral annuloplasty completed the procedure. Aortic and mitral insufficiency almost disappeared at follow-up. From the examination of this case and from a review of pertinent literature it emerges that in event of similar complex congenital abnormalities without intrinsic valve disease, a conservative approach should be chosen so that valve replacement can be avoided.

Surgical management of tunnel-like subaortic stenosis via ventricular septal defect in a patient with the interrupted aortic arch

A 24-day-old male with interrupted aortic arch (type B), ventricular septal defect, and tunnel-like subaortic stenosis underwent a one-stage surgical treatment. The operative procedure comprised reconstruction of the aortic arch, transatrial excision of the subaortic fibromuscular tissue via the ventricular sepatal defect, and patch closure of the defect. The patient tolerated the procedure well and the postoperative echocardiography demonstrated a residual pressure gradient across the left ventricular outflow tract of 20 mmHg. Our result suggests that the transatrial surgical management of subaortic stenosis via the ventricular sepatal defect produces a safe and promising surgical option.

Surgical correction of subaortic stenosis via right ventriculotomy and septal resection in a dog

After 2 years of medical management with a beta-adrenoreceptor blocking agent, a 30-month-old castrated male Golden Retriever with subaortic stenosis was treated surgically because of progression of its condition. In an attempt to achieve complete relief of the left ventricular outflow obstruction, a modified Konno procedure consisting of right ventriculotomy and septal myectomy from the infundibular portion of the right ventricle was performed; this combination of procedures allowed wide resection of the septal portion of the left ventricular outflow obstruction. Two years after surgery, the mass of the dog's left ventricle had decreased and the peak calculated pressure gradient across the aortic valve had decreased to 40 mm Hg, compared with a preoperative value of 240 mm Hg; at that evaluation, the dog had gained weight and was able to play normally. It is suggested that use of this modified approach to the outflow tract may have a positive effect on long-term survival time in dogs with subaortic stenosis.

The modified Konno procedure for complex left ventricular outflow tract obstruction

BACKGROUND

Complex left ventricular outflow tract (LVOT) obstruction with normal aortic valve function requires aggressive resection in the subaortic region and preservation of the aortic valve. The modified Konno procedure allows generous exposure of the LVOT from the left ventricular apex to the inter leaflet trigones of the aortic valve. Widespread use of this procedure has been limited by concern over injury to the aortic valve, the conduction system, and possibility of residual ventricular septal defect (VSD).

METHODS

Retrospective analysis of pertinent data for all patients undergoing the modified Konno procedure (1994 to 2001) at the University of Iowa were reviewed.

RESULTS

The modified Konno procedure was used in 18 patients (age 1 to 31) for LVOT obstruction associated with diffuse narrowing of the LVOT (n = 7), a discrete fibrous ring (n = 7), or a fibrous ring associated with abnormal mitral attachments (n = 4). Eight patients had previously undergone LVOT resection. There were no perioperative deaths. Estimated LVOT peak gradients by echocardiogram were 70.4 +/- 24.2 mm Hg (preoperative) and 19.2 +/- 20.4 mm Hg (postoperative) at most recent followup (p < 0.001 vs preop). Aortic insufficiency was moderate in one patient (present preop) and mild or less in all other patients. There were no cases of permanent heart block. Small residual VSDs were present in five patients (28%). Median follow-up is 3.1 years.

CONCLUSIONS

The modified Konno procedure can effectively relieve complex LVOT obstruction and preserve aortic valve function. Extension of this procedure for use in the initial presentation of LVOT may be appropriate in cases at increased risk of recurrent LVOT obstruction.

Subaortic stenosis: at risk substrates and treatment strategies

Subaortic stenosis can be a complex disease of multiple anatomic etiologies. At the core is either an elongated and narrow outflow tract as compared to normal or a fully muscle-rimmed VSD used as an intraventricular routing pathway. An array of treatment modalities is needed for an effective management strategy.

Left ventricular outflow tract obstruction after partial atrioventricular septal defect repair

BACKGROUND

Narrowing of the left ventricular outflow tract has been associated with partial atrioventricular septal defect (PAVSD) in about 3% of patients. Because of the predisposing anatomy, hemodynamically significant obstruction in the subaortic area may appear after repair of ostium primum atrial septal defects.

METHODS

From 1984 to 1998, 40 patients underwent surgical correction of PAVSD by patch closure. The mean age at the initial repair was 5.8 years (range 3 months to 22 years).

RESULTS

Nine patients had 12 subsequent operations for hemodynamically significant subaortic obstruction. The mean age at PAVSD repair was 17 months (3 to 42 months) (p < 0.001 compared with others). Follow-up work-up was obtained due to symptoms in 5 patients and an abnormal echocardiogram in 4 asymptomatic patients. Subaortic stenosis developed at a mean of 5 years (range 4 months to 10 years), and 6 or more years in 4 patients. The mean age at subaortic stenosis repair was 6 years (range 2 to 12 years). Nine patients underwent subaortic fibromuscular resection. Of these, 4 developed recurrent stenosis and 2 have undergone additional operations.

CONCLUSIONS

Left ventricular outflow tract obstruction after PAVSD repair may be more frequent than reported. Because of the progressive nature of the process, echocardiography should be utilized liberally on patients to uncover subclinical stenosis. Long-term follow-up is essential for diagnosis due to delayed appearance and lack of reliable clinical signs.