Aortocaval compression resulting in sudden loss of consciousness and severe bradycardia and hypotension during cesarean section in a patient with subvalvular aortic stenosis.

BACKGROUND: Maternal cardiac arrest during cesarean section (CS) is an extremely rare but devastating complication. Preventing emergency events from developing into maternal cardiac arrest is one of the most challenging clinical scenarios. CASE PRESENTATION: A 35-year-old pregnant woman with subvalvular aortic stenosis who was scheduled for elective CS under epidural anesthesia, and experienced devastating supine hypotensive syndrome, but was successfully resuscitated after delivery. CONCLUSIONS: The performance of tilt position strictly or high-quality continue manual left uterine displacement (LUD) should be performed until the fetus is delivered, otherwise timely delivery of the fetus may be the best way to optimize the deadly condition.

When Is It Better to Wait? Surgical Timing and Recurrence Risk for Children Undergoing Repair of Subaortic Stenosis.

Recurrence of subaortic stenosis (SAS) after surgery is common in children. The effects of patient characteristics and surgical timing on disease recurrence are largely unknown. We performed a retrospective study, assessing the relative effects of patient age and left ventricular outflow tract (LVOT) gradient on the need for reoperation for recurrent SAS. We included all children <20 years of age who underwent initial surgical resection of SAS at our center, January 2003-December 2013. Stratified logistic regression was performed, considering the effects of patient demographics, clinical characteristics, echocardiographic parameters, and operative technique, and clustering standard errors by surgeon. The multivariable model was used to simulate predicted probabilities of recurrent SAS for children at varying ages and baseline LVOT gradients. Sixty-three patients (38 males) underwent initial operation for SAS. Patients were followed for a median of 3.7 years (IQR 1.2-7.1). Twenty-one percent of patients (n = 13) underwent reoperation for SAS. Twelve were male. For every 10 mmHg increase in preoperative peak gradient in boys, the odds of reoperation for SAS doubled (OR 2.01, CI 1.5-2.72, p < 0.001), and for every additional 6 months of age, the odds of reoperation decreased by 14% (OR 0.86, CI 0.84-0.88, p < 0.001). Both younger age and higher preoperative outflow tract gradient are independently associated with risk of reoperation. Clinicians should consider the age and rate of LVOT gradient change-and not just the absolute gradient-in determining initial surgical timing.

A modified technique of Konno aortoventriculoplasty for redo aortic valve replacement procedures.

This article puts forward a modified technique of Konno aortoventriculoplasty for repeat procedures. After incision of the ventricular septum, this approach involves aortic valve replacement using a mechanical valved conduit, reimplantation of the coronary arteries, and graft replacement of the ascending aorta. This modification allows the removal of the diseased ascending aortic wall caused by a previous patch enlargement or poststenotic dilation.

Surgical management of subaortic stenosis.

A 63-year-old male patient with subaortic stenosis (Pmax 105 mmHg, Pmean 55 mmHg) and an aneurysm of the ascending aorta was referred to our hospital due to progressive angina pectoris. Transesophageal echocardiography demonstrated high and turbulent subaortic flow velocities. A calcified subaortic membrane was identified. The membrane was removed and the aneurysm was treated with a Bentall procedure. The patient recovered smoothly from surgery and was doing well 6 months after discharge.

The natural history of congenital subaortic stenosis.

BACKGROUND: Congenital subaortic stenosis (SAS) has a high recurrence rate after surgical correction. Aortic valve disease frequently coexists with SAS, being its occurrence and progression unpredictable. We aimed to assess predictors of SAS recurrence and aortic valve disease occurrence and progression. METHODS: Retrospective analysis of 51 patients with SAS followed in a congenital heart disease clinic of a tertiary care hospital from July 1982 to October 2009. RESULTS: The mean age at SAS diagnosis was 15 years and 28 patients (54.9%) were men. Aortic regurgitation was present in 23 (45.1%) patients. Thirty-four (66.7%) patients were submitted to SAS surgical correction, six (17.6%) of them also with aortic valve repair/replacement. Eighteen (52.9%) patients had SAS recurrence and eight patients (23.5%) underwent reoperation. A shorter time from diagnosis to surgery (odds ratio [OR] 0.98 [95% confidence interval, CI 0.96-1.00]; P= 0.04) and a left ventricular outflow tract (LVOT) peak pressure gradient at diagnosis > 50 mm Hg (OR 2.63 [95% CI 1.52-4.53]; P= 0.05) were independent predictors of SAS recurrence. At the end of follow-up, 37 patients (72.5%) had some form of aortic valve disease and 24 patients (47.1%) had progression for or of the aortic valve disease. Higher LVOT peak pressure gradient at diagnosis (OR 1.10 [95% CI 1.01-1.21]; P= 0.05) and higher left ventricular mass (OR 1.04 [95% CI 1.01-1.07]; P= 0.014) were independent predictors of aortic valve disease. Predictors of aortic valve disease progression were not found. CONCLUSIONS: SAS recurrence occurred mainly in patients operated sooner and with a high LVOT peak pressure gradients, suggesting a more severe form of disease. A more turbulent systolic jet at LVOT was probably one of the main causes of aortic valve damage. Aortic valve disease progression occurred independently of surgery and SAS recurrence. All LVOT morphological anomalies should be detected and corrected in order to prevent SAS recurrence and aortic valve disease.

The dilemma of subaortic stenosis--a single center experience of 15 years with a review of the literature.

OBJECTIVE: The term "subaortic stenosis" includes a variety of obstructions of the left ventricular outflow tract (LVOT), ranging from a short (discrete) subvalvular membrane to long, tunnel-like narrowing. An association with other congenital lesions is frequent. We reviewed the reported literature and describe our results, analyzing the nomenclature of and risk factors for restenosis after surgical treatment. METHODS: From 1994 to 2009, 81 children (53 males, 28 females; median age: 57 months, range [ R]: 5-204) underwent surgical relief of a subaortic stenosis. Patients were divided, according to pathology, into short segment (group A, n = 42) and complex obstructions (group B, n = 39), with the latter including long segment stenosis and/or associated anomalies such as aortic coarctation, interrupted aortic arch or Shone's complex. RESULTS: Surgery resulted in a significant reduction of the gradient between the left ventricle and the aorta in both groups (Δ P group A: 51 ± 28 mmHg, group B: 46 ± 25 mmHg). There was no operative mortality. One patient died in the early postoperative period due to pericardial tamponade. Median follow-up was 90 months (R = 0.5-187). Twenty-five (31%) patients required reoperation because of recurrent stenosis after a median of 43 months (R = 0.5-128). Seven (16%) patients belonging to group A developed restenosis, and 18 (46%) in group B. Freedom from reoperation for all patients was 60% after 10 years. 10 (40%) of the patients of group B were ultimately treated with a Ross-Konno reconstruction of the LVOT. CONCLUSION: Despite adequate surgical resection, recurrence of subaortic stenosis within several years after initial surgical treatment is frequent, especially in patients with complex lesions. In cases requiring reoperation, the surgical therapy is often extensive, and even includes Ross-Konno reconstruction of the LVOT.

Treatment of severe valvular aortic stenosis and subvalvular discrete subaortic stenosis and septal hypertrophy with Percutaneous CoreValve Aortic Valve Implantation.

BACKGROUND: Percutaneous aortic valve implantation (PAVI) is a procedure gaining popularity and becoming more widely used for the treatment of patients with severe aortic stenosis who are at high risk for surgery. Here we show, for the first time, that a successful and complete elimination of both valvular and subvalvular pressure gradients can be achieved with a slight modification of the valve implantation technique. METHODS AND RESULTS: A 91-year-old woman presented with shortness of breath at rest, effort angina, and pulmonary congestion. Echocardiography revealed calcified aortic stenosis with a peak gradient of 75 mm Hg across the valve, and discrete subaortic stenosis (DSS) and marked hypertrophy of the basal septum with systolic anterior motion of the mitral valve (SAM). The intra ventricular gradient had a dynamic pattern across the DSS and the septal hypertrophy and measured 75 mm Hg. The total gradient across the left ventricular outflow (valvular and subvalvular) was 125 mmHg. PAVI with a 23 mm CoreValve was performed with an intentional lower positioning of the valve towards the LV outflow tract; so that the valve struts cover the subaortic membrane and part of the thickened basal septum. At the end of the procedure, the SAM disappeared, and the left ventricular ouflow was widely open. At 1 month follow up the patient was asymptomatic, no pressure gradient was measured between the LV apex and the aorta. CONCLUSIONS: This is the first report of successful treatment of severe valvular aortic stenosis and combined subvalvular aortic stenosis due to DSS and septal hypertrophy with SAM with percutaneous aortic valve implantation.

Predictors of survival after aortic valve replacement in patients with low-flow and high-gradient aortic stenosis.

AIMS: To identify predictors of survival following aortic valve replacement (AVR) in patients with low-flow and high-gradient aortic stenosis (AS). METHODS AND RESULTS: Eighty-six patients (aged 71 +/- 10 years) with severe AS [aortic valve mean pressure gradient >40 mmHg or valve area <1.0 cm(2)] and left ventricular (LV) dysfunction [ejection fraction (EF) <50%] underwent AVR. Cox proportional hazards were used to identify independent clinical and echocardiographic predictors of mortality. Operative (30-day) mortality was 10%. Peri-operative mortality was associated with lower mean LVEF, higher mitral E:A ratio, peak systolic pulmonary artery pressure (PSPAP), and serum creatinine (by 12%, 2.3, 28 mmHg, and 74 mmol/L, respectively, all P < 0.001), NYHA class III-IV (100 vs. 65%), concomitant CABG (89 vs. 55%), urgent surgery (78 vs. 35%), and longer bypass-time (by 28 min, all P < 0.05). Mortality at 4 years was 17%. Univariate predictors [hazard ratio (HR)] of 4-year mortality were: lower EF (HR 0.68 per % increase, P < 0.001), presence of restrictive LV filling (HR: 3.52, P < 0.001), raised PSPAP (HR: 1.07, P < 0.001), and CABG (HR: 4.93, P = 0.037). However, only low EF (<40%, HR 0.74, P = 0.030), the presence of restrictive filling (HR 1.77, P = 0.033), and raised PSPAP (>45 mmHg, HR 2.71, P = 0.010) remained as independent predictors after multivariate analysis. CONCLUSION: The severity of pre-operative systolic and diastolic LV dysfunction is the major predictor of mortality following AVR for low-flow and high-gradient AS.

Risk factors for reoperation after relief of congenital subaortic stenosis.

BACKGROUND: Congenital subaortic stenosis entails a lesion spectrum, ranging from an isolated obstructive membrane, to complex tunnel narrowing of the left outflow associated with other cardiac defects. We review our experience with this anomaly, and analyze risk factors leading to restenosis requiring reoperation. METHODS: From 1994 to 2006, 58 children (median age 4.3 years, range 7 days-13.7 years) underwent primary relief of subaortic stenosis. Patients were divided into simple lesions (n=43) or complex stenosis (n=15) associated with other major cardiac defects. Age, pre- and postoperative gradient over the left outflow, associated aortic or mitral valve insufficiency, chromosomal anomalies, arteria lusoria, and operative technique (membrane resection (22) vs associated myectomy (34) vs Konno (2)) were analyzed as risk factors for reoperation (Kaplan-Meier, Cox regression). RESULTS: There was no operative mortality. Median follow-up spanned 2.7 years (range 0.1-10), with one late death at 4 months. Reoperation was required for recurrent stenosis in 11 patients (19%) at 2.6 years (range 0.3-7.5) after initial surgery. Risk factors for reoperation included complex subaortic stenosis (p=0.003), younger age (p=0.012), postoperative residual gradient (p=0.019), and the presence of an arteria lusoria (p=0.014). For simple lesions, no variable achieved significance for stenosis recurrence. CONCLUSIONS: Surgical relief of congenital subaortic stenosis, even with complex defects, yields excellent results. Reoperation is not infrequent, and should be anticipated with younger age at operation, complex defects, residual postoperative gradient, and an arteria lusoria. Myectomy concomitant to membrane resection, even in simple lesions, does not provide enhanced freedom from reoperation, and should be tailored to anatomic findings.

Prevalence and associated risk factors for intervention in 313 children with subaortic stenosis.

BACKGROUND: We sought to determine the prevalence of intervention and associated factors in children presenting with subaortic stenosis. We also investigated whether a protocol adopted in 1994 of early subaortic resection at a preoperative mean systolic gradient across the left ventricular outflow tract (LV gradient) greater than 30 mm Hg was supported by longitudinal outcomes. METHODS: Record review of all children (n = 313) diagnosed with subaortic stenosis was conducted between 1975 and 1998 at our institution. Cox proportional hazard models determined the prevalence and associated factors for initial subaortic resection. Mixed models of serially obtained echocardiographic data (n = 933) established longitudinal LV gradient trends and identified factors associated with more rapid LV gradient progression. RESULTS: Median age at presentation was 8 months. Freedom from initial subaortic resection was 40% at 16 years from diagnosis. Earlier progression to subaortic resection was associated with patient characteristics at presentation, including a higher initial LV gradient (p < 0.001), larger aortic annulus z-score (p = 0.005), smaller body surface area (p < 0.001), and smaller mitral annulus z-score (p = 0.003). Initial resection was also associated with a faster rate of LV gradient progression (p = 0.003). Factors determining the increased rate of LV gradient progression included an initial LV gradient greater than 30 mm Hg (p < 0.001), initial aortic valve thickening (p = 0.003), and attachment of subaortic stenosis to the mitral valve (p = 0.003). Worse aortic regurgitation grade with time was also associated with an initial LV gradient greater than 30 mm Hg (p < 0.001). CONCLUSIONS: Subaortic resection should be delayed until the LV gradient exceeds 30 mm Hg because most children with an initial LV gradient less than 30 mm Hg have quiescent disease.

Left subclavian artery to descending aorta bypass for coarctation physiology after descending aortic repair.

Stenosis of the aorta observed after descending aorta replacement for traumatic aortic injury was managed by a placement of a bypass between the left subclavian artery and the distal descending aorta with success.

Plasma concentrations and cardiovascular influence of lidocaine infusions during isoflurane anesthesia in healthy dogs and dogs with subaortic stenosis.

OBJECTIVE: To determine the plasma concentrations and cardiovascular changes that occur in healthy dogs and dogs with aortic stenosis that are given an infusion of lidocaine during isoflurane anesthesia. STUDY DESIGN: Phase 1, controlled randomized cross-over trial; Phase 2, before and after trial ANIMALS: Phase 1, 6 healthy dogs (4 female, 2 male) weighing 23.8 +/- 7.4 kg; Phase 2, 7 dogs (4 female, 3 male) with moderate to severe subaortic stenosis (confirmed by Doppler echocardiography) weighing 31.1 +/- 14.5 kg. METHODS: After mask induction, intubation, and institution of positive pressure ventilation, instrumentation was performed to measure hemodynamic variables. After baseline, measurement at an end-tidal isoflurane concentration of 1.9% (phase 1) or 1.85% (phase 2), a loading dose infusion of lidocaine at 400 microg/kg/min was given. Phase 1: Maintenance doses of lidocaine were administered consecutively (40, 120, and 200 microg/kg/min) after the loading dose (given for 10, 10, and 5 minutes, respectively) in advance of each maintenance concentrations. Measurements were taken at the end of each loading dose and at 25 and 35 minutes during each maintenance level. The same animals on a different day were given dextrose 5% and acted as the control. Phase 2: Dogs were studied on a single occasion during an infusion of lidocaine at 120 microg/kg/ min given after the loading dose (10 minutes). Measurements occurred after the loading dose and at 25 and 35 minutes. A blood sample for lidocaine concentration was taken at 70 minutes. Data were compared using a one-way ANOVA for phase 1, and between phase 1 and 2. Statistical analysis for phase 2 was performed using a paired t-test with a Bonferroni correction. A P value < or = .05 was considered significant. RESULTS: Phase 1: Plasma lidocaine concentrations achieved with 40, 120, and 200 microg of lidocaine/kg/min were 2.70, 5.27, and 7.17 microg/mL, respectively. A significant increase in heart rate (HR) (all concentrations), central venous pressure (CVP), mean pulmonary arterial pressure (PAP), and a decrease in stroke index (SI) (200 microg/kg/min) were observed. An increase in systemic vascular resistance (SVR) and mean PAP, and a decrease in SI also followed the loading dose given before the 200 microg/kg/min infusion. No other significant differences from the control measurements, during dextrose 5% infusion alone, were detected. Phase 2: Plasma lidocaine concentrations achieved were 5.35, 4.23, 4.23, and 5.60 microg/mL at 10, 25, 35, and 70 minutes, respectively. They were not significantly different from concentrations found in our healthy dogs at the same infusions. A significant but small increase in CVP compared with baseline was noted after the loading dose. There were no significant differences from baseline shown in all other cardiovascular data. There were no statistically significant differences in any measurements taken during the lidocaine infusion between the dogs in phase 1 and phase 2. Dogs with aortic stenosis tended to have a lower cardiac index than healthy dogs at baseline (88 v 121 mL/kg/min) and during lidocaine infusion (81 v 111 mL/kg/min). A small, statistically significant difference in systolic PAP was present at baseline. CONCLUSIONS: There does not appear to be any detrimental cardiovascular effects related to an infusion of lidocaine at 120 microg/kg/min during isoflurane anesthesia in healthy dogs or dogs with aortic stenosis. The technique used in this study resulted in therapeutic plasma concentrations of lidocaine. CLINICAL RELEVANCE: Methods shown in the study can be used in clinical cases to achieve therapeutic lidocaine levels without significant cardiovascular depression during isoflurane anesthesia.

Benefits of early surgical repair in fixed subaortic stenosis.

OBJECTIVES: We sought to determine whether early resection can improve outcome in fixed subaortic stenosis. BACKGROUND: The diagnosis of subaortic stenosis (SAS) is often made before significant gradients occur. Whereas resection is the accepted treatment, it remains uncertain whether surgical intervention at this early stage can reduce the incidence of recurrence or influence the progression of aortic valve damage. METHODS: Follow-up was available for 75 of 83 consecutive patients operated on for fixed SAS; the average duration of follow-up was 6.7 years. The lesion was discrete in 68 patients (91%) and of a tunnel type in 7, with associated ventricular septal defect in 28 (37%). All underwent transaortic resection. RESULTS: There were no deaths. There were 18 recurrences of SAS in 15 patients (20%). Thirteen patients (17%) underwent 17 reoperations for recurrence or aortic valve disease. The cumulative hazard of recurrence was 8.9%, 16.1% and 29.4% +/- 2.3% (mean +/- SEM), and the hazard of events, including recurrence and reoperation, was 9.2%, 18.4% and 35.1% +/- 3.5% at 2, 5 and 10 years, respectively. Residual end-operative left ventricular outflow tract (LVOT) gradients (> 10 mm Hg, n = 8) and tunnel lesions were univariate predictors of recurrence (p = 0.0006 and p = 0.003, respectively). Multivariate predictors included higher preoperative LVOT gradient (p < 10(-4)) and younger patient age (p = 0.002). Only two recurrences (0.87 per 100 patient-years of follow-up) were noted in patients with a preoperative peak LVOT gradient < or = 40 mm Hg (n = 40), whereas higher gradients (n = 35) were associated with a greater than sevenfold recurrence rate (6.45 events per 100 patient-years, p = 0.002). The aortic valve required concomitant repair in 17 cases in the high gradient group (48.6%) but in only 8 in the low gradient group (20%, p = 0.018). Despite relief of the obstruction, progressive aortic regurgitation was noted at follow-up after 14 procedures in the high gradient group (40%) but after only 5 procedures in the low gradient group (12.5%, p = 0.014). CONCLUSIONS: The data suggest that surgical resection of fixed subaortic stenosis before the development of a significant (> 40 mm Hg) outflow tract gradient may prevent recurrence, reoperation and secondary progressive aortic valve disease.

Subaortic stenosis due to accessory tissue of the mitral valve associated with Ebstein's anomaly in an adult.

A 26-year-old man with a history of effort-induced syncopal attacks was found to have Ebstein's anomaly. A cardiac catheterization revealed a pressure gradient of 77 mmHg between the left ventricle outflow tract which was caused by mitral accessory tissue. The accessory tissue was resected, the aortic valve was replaced, and the Ebstein's anomaly was corrected. The degree of mitral regurgitation was seen to increase following surgery. This is the first reported case of an accessory mitral valve complicated with Ebstein's anomaly.

Transoesophageal echocardiographic assessment of fixed subaortic obstruction in children.

OBJECTIVE: To evaluate the clinical usefulness of transoesophageal echocardiography in the assessment of children with fixed left ventricular outflow tract stenosis. PATIENTS AND METHODS: Eight consecutive children, aged over 5 years, with fixed subaortic stenosis and one child with fixed subpulmonary left ventricular outflow tract stenosis were prospectively assessed by precordial and transoesophageal echocardiography. RESULTS: Transoesophageal images of the left ventricular outflow tract were much clearer than precordial images in all patients except one with a prosthetic mitral valve. Improved visualisation provided further information on the nature of the lesion (additional chordal attachment of the mitral valve in one, accessory atrioventricular valve tissue with aneurysm formation in one), on the extent of the lesion (circumferential in three), and on the very close relation of a ridge to the aortic valve leaflets in one. Transoesophageal Doppler did not provide any additional information on aortic regurgitation and was unreliable for gradient estimation across the left ventricular outflow tract. CONCLUSIONS: Transoesophageal imaging provides an excellent means of visualising lesions in the left ventricular outflow tract and can be useful in a few children and adolescents in whom precordial echocardiography does not provide adequate information. The technique can also be used intraoperatively to define the full extent of the obstructive lesion and to assess residual lesions after surgery.

Cardiac function after surgery for subaortic stenosis: non-invasive assessment of left ventricular performance.

OBJECTIVE: To examine left ventricular function after surgical resection of subaortic stenosis during childhood. DESIGN: Left ventricular performance was measured non-invasively in all patients who responded to an invitation for formal assessment. SETTING: Outpatient study, tertiary referral centre. PATIENTS: Twenty three (12 male and 11 female) patients (age range 3 to 31 years) of 43 consecutive patients with fixed subaortic stenosis undergoing surgical resection between 1975 and 1989 reattended for formal assessment 16 months to 15 years (median 4 years 4 months) after operation. MAIN OUTCOME MEASURES: Left ventricular dimension, left ventricular wall thickness, left ventricular Doppler inflow velocities, and left ventricular diastolic pressure (measured from apexcardiograms). Results were compared with those in controls individually matched for age and sex. RESULTS: All patients were symptom free. Left ventricular cavity dimensions were normal, as was the mean fractional shortening. Posterior wall thickness tended to be greater in the patients and there was a significant increase in septal thickness. Normalised peak rate of posterior wall thinning was significantly lower in the patients and the isovolumic relaxation time was significantly shorter. Doppler inflow velocity measurements showed that early diastolic mitral flow acceleration time was normal but deceleration time was significantly shorter in the patients. The ratio of mitral flow in early diastole (E) to E plus mitral flow in late diastole (A) was significantly higher in the patients and in two patients there was complete absence of A wave flow despite large A waves on the apexcardiogram. CONCLUSIONS: Systolic function was well preserved in patients after operation for subaortic stenosis. A restrictive pattern of left ventricular filling was common, however, and presumably reflected a response to the chronic pressure load and to surgery in the paediatric heart.

[Balloon dilatation of subvalvular membranous stenosis of the aorta in an 8-year-old boy]. / Balónková dilatace subvalvární membranózní stenózy aorty u osmiletého chlapce.

Case-history of an eight-year-old boy with subvalvular membranous aortal stenosis where the authors used for treatment percutaneous dilatation by means of a balloon catheter without using surgery. The authors recommend to eliminate the stenosis as soon as possible before serious aortal insufficiency develops.