Aortic valve replacement in geriatric patients: determinants of in-hospital mortality

Men are from mars, women are from venus: Factors responsible for gender differences in outcomes after surgical and trans-catheter aortic valve replacement

Females suffer higher operative (30-day) mortality than males after surgical aortic valve replacement (SAVR). In contrast, outcomes after trans-catheter aortic valve replacement (TAVR) seem to favor females, both in terms of procedural mortality, and more prominently, medium to long-term survival. With an ever-greater number of TAVR procedures being performed, an understanding of factors responsible for gender differences in outcomes after the two AVR modalities is critical for better patient selection. Current evidence suggests that this gender difference in outcomes after SAVR and TAVR stems from differences in baseline risk profiles, as well as inherent anatomic/physiological differences between genders. This review attempts to examine these clinical and physiological factors, with a goal of guiding better patient selection for each AVR modality, and to highlight areas that beg further investigation.

Aortic valve bypass surgery in severe aortic valve stenosis: Insights from cardiac and brain magnetic resonance imaging

OBJECTIVE

To investigate and describe the distribution of aortic and cerebral blood flow (CBF) in patients with severe valvular aortic stenosis (AS) before and after aortic valve bypass (AVB) surgery.

METHODS

We enrolled 10 consecutive patients who underwent AVB surgery for severe AS. Cardiovascular magnetic resonance imaging (CMR) and brain magnetic resonance imaging were performed as baseline before surgery and twice after surgery. Quantitative flow measurements were obtained using 1.5-T magnetic resonance imaging (MRI) scanner phase-contrast images of the ascending aorta, descending thoracic aorta (3 cm proximally and distally from the conduit-to-aorta anastomosis), and ventricular outflow portion of the conduit. The evaluation of CBF was performed using 3.0-T MRI scanner arterial spin labeling (ASL) through sequences acquired at the gray matter, dorsal default-mode network, and sensorimotor levels.

RESULTS

Conduit flow, expressed as the percentage of total antegrade flow through the conduit, was 63.5 ± 8% and 67.8 ± 7% on early and mid-term postoperative CMR, respectively (P < .05). Retrograde perfusion from the level of the conduit insertion in the descending thoracic aorta toward the aortic arch accounted for 6.9% of total cardiac output and 11% of total conduit flow. We did not observe any significant reduction in left ventricular stroke volume at postoperative evaluation compared with preoperative evaluation (P = .435). No differences were observed between preoperative and postoperative CBF at the gray matter, dorsal default-mode network, and sensorimotor levels (P = .394).

CONCLUSIONS

After AVB surgery in patients with severe AS, cardiac output is split between the native left ventricular outflow tract and the apico-aortic bypass, with two-thirds of the total antegrade flow passing through the latter and one-third passing through the former. In our experience, CBF assessment confirms that the flow redistribution does not jeopardize cerebral blood supply.

A Retrospective Analysis of the Variability in Case Duration for Aortic Valve Replacement and Association With Hospital Facility Types

OBJECTIVE

Currently, there are no large-scale studies that compare differences in case duration of aortic valve replacements (AVRs). The primary objective of this study was to determine associations of hospital facility type, geographic location, case volume per year, and time of day with duration of valve replacement surgery.

DESIGN

Retrospective.

SETTING

Data from the National Anesthesia Clinical Outcomes Registry.

PARTICIPANTS

National data from university and non-university hospitals.

INTERVENTIONS

No interventions.

MEASUREMENTS AND MAIN RESULTS

All AVRs from the National Anesthesia Clinical Outcomes Registry were identified from 2010 to 2014. Mean case duration for all AVRs was 360.8 ± 95.8 minutes and was presented based on facility type (university hospital, large community hospital, medium-sized community hospital, and other); US geographic region; time of day (cases performed after 5 pm and before 7 am v day shift); and case volume per year. A multivariable linear regression model was built to determine the association of various patient, procedural, and facility characteristics with case duration. University hospitals were associated with increased case duration for AVRs (p < 0.0001).

CONCLUSIONS

With this large national database, the authors demonstrated that academic hospitals, time of day of the surgery, US region, and case volume per year for a facility are related to the case duration of AVRs.

Early and Mid-term Outcome of the St. Jude Medical Regent 19-mm Aortic Valve Mechanical Prosthesis. Functional and Haemodynamic Evaluation

BACKGROUND AND OBJECTIVES

The aim of the present study is to report the early and mid-term clinical and haemodynamic results of the St Jude Medical Regent 19-mm aortic mechanical prothesis (SJMR-19).

MATERIALS AND METHODS

Between January 2002 and January 2012, 265 patients with aortic valve disease underwent AVR (Aortic Valve Replacement) with a SJMR-19 (St Jude Medical Regent Nr.19). There were 51 males. Mean age was 67.5±12.72years and mean body surface area (BSA) was 1.67±0.14m2. Thirty-six patients required annulus enlargement. The mean follow-up was 34.5±18.8months (range 6-60 months). All patients underwent echocardiographic examination at discharge and within 1 year after surgery.

RESULTS

There were 14 (5.3%) hospital deaths. Six of the hospital deaths were identified in patients undergoing reoperation, significantly higher than patients undergoing first time operation (p=0.0001). Also the postoperative mortality was significantly higher in patients undergoing annulus enlargement versus patients not requiring annulus enlargement (p=0.02). The mean transprosthesis gradient at discharge was 19±9mmHg. At 6 months follow-up the mean NYHA FC class was 1.6±0.5 significantly lower than preoperatively 2.4±0.75 (p <0.0001). The M-TPG was 15.2±6.5mmHg within 1 year after surgery. Left ventricular mass (LVM) and indexed left ventricular mass (LVM_i) were significantly lower than preoperatively The actuarial survival and cumulative freedom from reoperation at 1, 2 and 3 years follow-up were 99.5%, 97.5%, 96.7% and 99.2%, 96.5%, 94.5% respectively. The cumulative actuarial free-events survival at 4 years was 92%. The Cox model identified age (p=0.015), LVEF≤35% (p=0.043), reoperation (p=0.031), combined surgery (p=0.00002), and annulus enlargement (p=0.015) as strong predictors for poor actuarial free-major events survival.

CONCLUSIONS

The SJMR-19 offers excellent postoperative clinical, haemodynamic outcome and LVM_i reduction in patients with small aortic annulus. These data demonstrate that the modern St Jude small mechanical protheses do not influence the intermediate free-reoperation survival.

An Early Canadian Experience With the Correx Automated Coring and Apical Connector Device for Aortic Valve Bypass

OBJECTIVE

Aortic valve replacement is the standard of care for severe, symptomatic aortic valve stenosis (AS); however, anatomy or pre-existing comorbidities may preclude conventional or alternative transcatheter approaches. Aortic valve bypass (AVB) may be performed as a salvage procedure for the relief of symptomatic aortic stenosis in patients who are not suitable candidates for aortic valve replacement.

METHODS

At our institution, seven patients underwent AVB using the Correx automated coring and apical connector system. All patients had severe AS with New York Heart Association functional class 3 symptoms and were not candidates for conventional or transcatheter approaches. Via a left anterolateral thoracotomy to access the descending aorta and left ventricular apex, we used the Correx system (Correx, Waltham, MA USA) to anastomose a valve conduit to the left ventricular apex proximally and the descending aorta distally. Three patients required cardiopulmonary bypass.

RESULTS

In all seven patients, the automated coring and apical connector was successfully deployed. There were two in-hospital deaths in this series. Immediately postoperatively and at 3 months, there was a significant reduction in mean and peak valve gradients, and all surviving patients performed at New York Heart Association functional class 1.

CONCLUSIONS

Aortic valve bypass seems to be an acceptable alternative for the treatment of severe AS in high-risk patients who are not candidates for aortic valve replacement. The Correx automated system may improve the clinical applicability and surgical reproducibility of AVB in appropriately selected patients in which conventional or transcatheter aortic valve replacement is not a feasible options.

Prognosis of Prolonged Intensive Care Unit Stay After Aortic Valve Replacement for Severe Aortic Stenosis in Octogenarians

OBJECTIVES

Octogenarians considered for cardiac surgery encounter more complications than other patients. Postoperative complications raise the question of continuation of high-cost care for patients with limited life expectancy. Duration of hospitalization in intensive care after cardiac surgery may differ between octogenarians and other patients. The objectives were evaluating the mortality rate of octogenarians experiencing prolonged hospitalization in intensive care and defining the best cut-off for prolonged intensive care unit length of stay.

DESIGN

A single-center observational study.

SETTING

A postoperative surgical intensive care unit in a tertiary teaching hospital in Paris, France.

PARTICIPANTS

All consecutive patients older than 80 years considered for aortic valve replacement for aortic stenosis were included.

MEASUREMENTS AND MAIN RESULTS

Mortality rate was determined among patients experiencing prolonged stay in intensive care with organ failure and without organ failure. An ROC curve determined the optimal cut-off defining prolonged hospitalization in intensive care according to the occurrence of postoperative complications. Multivariate analysis determined risk factors for early death or prolonged intensive care stay. The optimal cut-off defining prolonged intensive care unit length of stay was 4 days. Low ventricular ejection fraction (odds ratio [OR] = 0.95; 95% confidence interval [CI] 0.96-0.83; p = 0.0016), coronary disease (OR = 2.34; 95% CI 1.19-4.85; p = 0.014), and need for catecholamine (OR = 2.79; 95% CI 1.33-5.88; p = 0.0068) were associated with eventful postoperative course. There was not a hospitalization duration beyond which the prognosis significantly worsened.

CONCLUSIONS

Prolonged length of stay in ICU without organ failure is not associated with increased mortality. No specific duration of hospitalization in intensive care was associated with increased mortality. Continuation of care should be discussed on an individual basis.

Function of the Respiratory System in Elderly Patients After Aortic Valve Replacement

OBJECTIVE

To compare the function of the respiratory system after aortic valve replacement through median sternotomy (AVR) or the minimally invasive right anterior minithoracotomy (RAT-AVR) approach among elderly (aged≥75 years) patients.

DESIGN

Observational cohort study.

SETTINGS

University hospital.

PARTICIPANTS

The study included 65 elderly patients scheduled for RAT-AVR and 82 for standard AVR.

INTERVENTIONS

Pulmonary function tests (PFT) were performed preoperatively, 1 week, 1 month, and 3 months after surgery. In addition, respiratory complications were analyzed.

MEASUREMENTS AND MAIN RESULTS

Respiratory complications occurred in 12.3% of patients in the RAT-AVR group and 18.3% of patients in the AVR group (p = 0.445). Mechanical ventilation time in the intensive care unit was 7.7±3.6 hours for RAT-AVR patients and 9.7±5.4 hours for AVR patients (p = 0.003). Most PFT were worse in the AVR group than in the RAT-AVR group when performed 1 week after surgery. After 1 month, forced expiratory volume in the first second, vital capacity, and total lung capacity differed significantly in favor of the RAT-AVR group (p = 0.002, p<0.001, and p = 0.001, respectively). After 3 months, the PFT parameters still had not returned to preoperative values, but the differences were no longer significant between the RAT-AVR and AVR groups. The multivariable median regression analysis demonstrated that RAT-AVR surgery was a key factor in a patient's higher postoperative PFT parameter values.

CONCLUSIONS

RAT-AVR surgery resulted in shorter postoperative mechanical ventilation time and improved the recovery of pulmonary function in elderly patients, but it did not reduce the incidence of pulmonary complications when compared with surgery performed through a median sternotomy.

Obesity and the risk of late mortality after aortic valve replacement with small prosthesis

BACKGROUND

Whether obesity is related to late mortality with implantation of small aortic prosthesis remains to be clarified. This study was aimed to evaluate the effect of obesity on late survival of patients after aortic valve replacement (AVR) with implantation of small aortic prosthesis (size ≤ 21 mm).

METHODS

From January 1998 to December 2008, 307 patients in our institution who underwent primary AVR with smaller prostheses survived the 30 days after surgery. Patients were defined as normal if body mass index (BMI) was < 24 kg/m2, as overweight if BMI 24-27.9 kg/m2, and as obese if BMI ≥ 28 kg/m2. Data of New York Heart Association (NYHA) functional classification, left ventricular ejection fraction (LVEF), effective orifice area index (EOAI), and left ventricular mass index (LVMI) of the patients collected at the 3rd month (M), 6th M, 1st year (Y), 3rd Y, 5th Y, 8th Y after operation respectively.

RESULTS

By multivariable analysis, obesity was an independent factor of late mortality (hazard ratio [HR]: 1.62; P = 0.01). The obesity and overweight group had more poor survival (p < 0.001) and higher proportion of NYHA class III/IV (p < 0.01) compared with the normal group. Lower EOAI and higher LVMI were found in obesity and overweight group, but we saw no significant difference about LVEF among the three groups.

CONCLUSIONS

Obesity was associated with increased late mortality of patients after AVR with implantation of small aortic prosthesis. Being obese or and overweight may also affect the NYHA classification, even in the longer term. EOAI should be improved where possible, as it may reduce late mortality and improve quality of life in obese or overweight patients.

Obesity is associated with higher long-term mortality after aortic valve replacement with small prosthesis

OBJECTIVE

Although many studies have evaluated the impacts of obesity on various medical treatments, it is not known whether obesity is related to late mortality with implantation of small aortic prosthesis. This study evaluated the effect of obesity on late survival of patients after aortic valve replacement (AVR) with implantation of small aortic prosthesis (size ≤ 21 mm).

METHODS

From January 1998 to December 2008, 536 patients in our institution who underwent primary AVR (307 patients with smaller prostheses) survived the 30 days after surgery. Patients were categorised as normal weight if body mass index (BMI) was ≤ 25 kg/m(2), as overweight if BMI 25-30 kg/m(2), and as obese if BMI ≥ 30 kg/m(2). Data were collected at the third-month (M), sixth-M, first-year (Y), third-Y, fifth-Y, and eighth-Y after operation.

RESULTS

By multivariable analysis, obesity was a significant independent factor of late mortality (hazard ratio [HR]: 1.59; p=0.006). The obese and overweight groups of patients exhibited lower survival (p<0.001) and a higher proportion in NYHA class III/IV (p<0.01) compared with the normal group. Lower EOAI and higher left ventricular mass index were found in the obese and overweight groups, but we saw no significant variance in LVEF among the three groups.

CONCLUSIONS

Obesity was associated with increased late mortality of patients after AVR with implantation of small aortic prosthesis. Being obese or and overweight may also affect the NYHA classification, even in the longer term.

Impact of obesity on long-term survival after aortic valve replacement with a small prosthesis

OBJECTIVES

Although many studies have evaluated the impact of obesity on various medical treatments, it is not known whether obesity is related to late mortality with implantation of small aortic prostheses. This study evaluated the effect of obesity on the late survival of patients after aortic valve replacement (AVR) with implantation of a small aortic prosthesis (size ≤ 21 mm).

METHODS

From January 1998 to December 2008, 307 patients in our institution who underwent primary AVR with smaller prostheses survived 30 days after surgery. Patients were categorized as normal weight if body mass index (BMI) was <24 kg/m(2), overweight if BMI 24-27.9 kg/m(2) and obese if BMI ≥ 28 kg/m(2). Data of the New York Heart Association (NYHA) functional classification, left ventricular ejection fraction (LVEF), effective orifice area index (EOAI) and left ventricular mass index of the patients were collected at the third month, sixth month, first year, third year, fifth year and eighth year after operation.

RESULTS

By multivariable analysis, obesity was a significant independent factor of late mortality (hazard ratio: 1.62; P = 0.01). The obese and overweight groups of patients exhibited lower survival (P < 0.001) and a higher proportion in NYHA Class III/IV (P < 0.01) compared with the normal group. A lower EOAI and higher left ventricular mass index were found in the obese and overweight groups, but we saw no significant variance in LVEF among the three groups.

CONCLUSIONS

Obesity is associated with increased late mortality of patients after AVR with implantation of small aortic prosthesis. Obesity or/and overweight may also affect the NYHA classification, even in the longer term. EOAI should be improved where possible, as it may reduce late mortality and improve quality of life in obese or overweight patients.

Aortic valve bypass: experience from Denmark

OBJECTIVES

In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI). During the last one and a half year, 10 patients otherwise left for medical therapy have been offered this procedure. We present the Danish experiences with the AVB procedure with a focus on patient selection, operative procedure and short-term results.

METHODS

AVB is performed through a left thoracotomy. A 19-mm Freestyle(®) valve (Medtronic) is anastomosed to a vascular graft and an apex conduit. The anastomosis to the descending aorta is made prior to connecting the conduit to the apex. In 1 patient, we used an automated coring and apical connector insertion device (Correx(®)). The device results in a simultaneous coring and insertion of an 18-mm left ventricle connector in the apical myocardium. AVB is routinely performed without circulatory assistance.

RESULTS

Ten patients have been operated on since April 2011: eight females and 2 males with a median age of 76 (65-91) years. Seven patients had a severely calcified ascending aorta. Three of these had previously had a sternotomy, but did not have an AVR because of porcelain aorta. Six patients had a very small left ventricle outflow tract (<18 mm). The median additive EuroSCORE was 12 (10-15). Seven patients were operated on without circulatory assistance. Two patients had a re-exploration for bleeding and 1 developed a ventricle septum defect 1 month postoperatively and was treated with surgical closure. The median follow-up was 7 (2-15) months and was without mortality. New York Heart Association class was reduced from 2.5 to 2 at the follow-up, but some patients were still in the recovery period. The total valve area (native plus conduit) was 2.2 (1.9-2.5) cm(2) and 1.34 (1.03-1.46) cm(2)/m(2), indexed to the body surface area. There was no AV block or stroke.

CONCLUSIONS

AVB can be performed with low mortality and acceptable results in selected patients. The procedure can be offered to patients rejected for conventional aortic valve replacement and TAVI and results in a larger total valve area than by insertion of standard bioprosthesis.

Sutureless Aortic Valve Implantation through an Upper V-Type Ministernotomy: An Innovative Approach in High-Risk Patients

Objective

Aortic valve replacement in minimally invasive approach has shown to improve clinical outcomes even with a prolonged cardiopulmonary bypass and aortic cross-clamp (ACC) time. Sutureless aortic valve implantation may ideally shorten operative time. We describe our initial experience with the sutureless 3f Enable (Medtronic, Inc, ATS Medical, Minneapolis, MN USA) aortic bioprosthesis implanted in minimally invasive approach in high-risk patients.

Methods

Between May 2010 and May 2011, thirteen patients with severe aortic stenosis underwent aortic valve replacement with the 3f Enable bioprosthesis through an upper V-type ministernotomy interrupted at the second intercostal space. The mean ± SD age was 77 ± 3.9 years (range, 72–83 years), 10 patients were women, and the mean ± SD logistic EuroSCORE was 15% ± 13.5%. Echocardiography was performed preoperatively, at postoperative day 1, at discharge, and at follow-up. Clinical data, adverse events, and patient outcomes were recorded retrospectively. The median follow-up time was 4 months (interquartile range, 2–10 months).

Results

Most of the implanted valves were 21 mm in diameter (19–25 mm). The CPB and ACC times were 100.2 ± 25.3 and 66.4 ± 18.6 minutes. At short-term follow-up, the mean ± SD pressure gradient was 14 ± 4.9 mm Hg; one patient showed trivial paravalvular leakage. No patients died during hospital stay or at follow-up.

Conclusions

The 3f Enable sutureless bioprosthesis implanted in minimally invasive approach through an upper V-type ministernotomy is a feasible, safe, and reproducible procedure. Hemodynamic and clinical data are promising. This innovative approach might be considered as an alternative in high-risk patients. Reduction of CPB and ACC time is possible with increasing of experience and sutureless evolution of actual technology.

Innovative technology-transcatheter aortic valve implantation: cost and reimbursement issues

OBJECTIVE

Transcatheter aortic valve implantation (TAVI) offers a new treatment option for patients with severe symptomatic aortic valve stenosis, classified as "inoperable". The purpose of the study was to reveal the association between ascertained hospital costs with the actual patient Diagnosis-Related Group (DRG).

METHOD

We examined 50 consecutive patients who underwent either transapical TAVI, (TAVI-TA) or transfemoral TAVI (TAVI-TF) with the Edwards SAPIEN valve and CoreValve(®) between September 2009 and August 2011.

RESULTS

Fourty-nine patients had successful valve deployment. Seven patients died within 30 days of the operation. The mean length of hospital stay for TAVI-TA was 199 hours (range 77-362), and the mean costs for TAVI-TA were 55,690 US$. For TAVI-TF the mean length of hospital stay was 170 hours (range 49-276) and the mean costs were 52,087 US$.

CONCLUSION

There was no significant difference between TAVI-TA and TAVI-TF patient characteristics. There was a significant discrepancy between actual hospital costs and the current Norwegian DRG reimbursement for the TAVI procedure. This discrepancy can be partly explained by excessive costs related to the introduction of a new program with new technology. Costly innovations should be considered in price-setting of reimbursement for novel technology.

Fluid Dynamic Investigation of the ATS 3F Enable Sutureless Heart Valve

OBJECTIVE

: Currently, sutureless heart valves (SHV) reveal good clinical results during aortic valve replacement. The aim of this study was to evaluate the fluid dynamics of the ATS 3F Enable SHV in the ascending aorta and their influence on the aortic wall in an in vitro setup.

METHODS

: A two-dimensional particle image velocimetry study with an image rate of 15 Hz was conducted to evaluate the fluid dynamics of the SHV in the aortic flow field. The prosthesis (diameter, 23 mm) was placed inside a silicone mock aorta under pulsatile flow conditions. Velocities, vorticity, and strain rate were obtained and calculated with a fixed frequency (70 Hz) at constant stroke volume (70 mL).

RESULTS

: 3F Enable showed a jet flow type profile with a maximum velocity of 1.01 ± 0.13 m/s during peak flow phase (PFP). The jet flow was surrounded by ambilateral vortices with a slightly higher percentage of clockwise than counterclockwise vorticity (377 ± 57/s vs 389 ± 76/s), strain rate (370 ± 79/s for elongation vs -370 ± 102/s for contraction) was nearly similar. The point-of-interest analysis revealed a higher velocity for bottom compared with upper aortic wall (0.28 ± 0.07 m/s vs 0.31 ± 0.06 m/s, P = 0.024). All values were lower during acceleration and deceleration phase compared with PFP.

CONCLUSIONS

: The peak flow of the 3F Enable SHV seems to be little higher compared with native aortic valves, thus simulating nearly physiologic conditions. Vorticity and strain rate are high during PFP and low during other phases and might have an influence on the aortic wall as well.

A novel device for endovascular native aortic valve resection for transapical transcatheter aortic valve implantation

We developed a novel resection device to use during transapical transcatheter aortic valve implantation (TAVI) using a circular blade. We assessed the device in 15 human cadavers by transapical approach. After the resection, the aortic annulus was measured using standard probes. A careful examination of the aortic wall, left ventricular outflow tract, coronary ostia and mitral valve was performed using an endpoint checklist, developed specifically for the new device. The resection was successfully completed in 14 out of 15 (93%) cases. All the resected leaflets and debris have been successfully evaluated in 15 out of 15 (100%) cases. One case of a bicuspid valve had a prominent calcification of the median raphe. The resection tool could only perform a partial resection. The mean duration of the resection was 45 ± 30 s. The surrounding tissue examination did not reveal any injury to the anatomical structures. Endovascular resection of the native valve using transapical approach is feasible and effective. Further developments are necessary before the definitive clinical use during percutaneous aortic valve implantation.

Automated coring and apical connector insertion device for aortic valve bypass surgery

PURPOSE

The technical difficulty of performing the left ventricular apical anastomosis has limited the adoption of aortic valve bypass surgery for the treatment of aortic stenosis. We report the successful use of an automated coring and apical connector device to perform aortic valve bypass surgery.

DESCRIPTION

A 74-year-old man, with a history of prior coronary bypass surgery with patent grafts and a porcelain ascending aorta, presented with symptomatic critical aortic stenosis. Through a left anterolateral thoracotomy, a valved conduit was anastomosed to the descending thoracic aorta. The automated coring and apical connector insertion device was used to core a plug of apical myocardium and simultaneously insert an 18-mm apical connector into the left ventricular apex.

EVALUATION

There were no procedural complications, cardiopulmonary bypass was not used, and estimated blood loss was minimal. The patient was discharged on postoperative day 5, and at 3-month follow-up demonstrated significant clinical and hemodynamic improvement.

CONCLUSIONS

The automated coring and apical connector insertion device facilitated the safe and effective performance of aortic valve bypass surgery.

Non-invasive cerebral oxygenation reflects mixed venous oxygen saturation during the varying haemodynamic conditions in patients undergoing transapical transcatheter aortic valve implantation

Transapical transcatheter aortic valve implantation (TA-TAVI) is increasingly used to treat aortic valve stenosis in high-risk patients. Mixed venous oxygen saturation (SvO(2)) is still the 'gold standard' for the determination of the systemic oxygen delivery to consumption ratio in cardiac surgery patients. Recent data suggest that regional cerebral oxygen saturation (rScO(2)) determined by near-infrared spectroscopy is closely related to SvO(2). The present study compares rScO(2) and SvO(2) in patients undergoing TA-TAVI. n = 20 cardiac surgery patients scheduled for TA-TAVI were enrolled in this prospective observational study. SvO(2) and rScO(2) were determined at predefined time points during the procedure. Correlation and Bland-Altman analysis of the complete data set showed a correlation coefficient of r(2 )= 0.7 between rScO(2) and SvO(2) (P < 0.0001), a mean difference (bias) of 5.8 with limits of agreement (1.96 SD) of -6.8 to 18.3% and a percentage error of 17.5%. At all predefined time points correlation was moderate (r(2 )= 0.50) to close (r = 0.84), and the percentage error was <24%. RScO(2) determined by near-infrared spectroscopy is correlated to SvO(2) during varying haemodynamic conditions in patients undergoing TA-TAVI. This suggests that rScO(2) is reflective not only of the cerebral, but also of the systemic oxygen balance.

Magnetic resonance investigation of blood flow after aortic valve bypass (apicoaortic conduit)

BACKGROUND

Aortic valve bypass (AVB, apicoaortic conduit) is an alternative to aortic valve replacement (AVR) for high-risk patients with aortic stenosis (AS). The redistribution of blood flow after AVB has been poorly characterized. In order to understand cardiovascular physiology after AVB, we performed cardiac magnetic resonance (CMR) imaging of AVB recipients.

METHODS

Fifteen patients with symptomatic AS underwent beating-heart AVB. Electrocardiography-gated two-dimensional phase-contrast velocity mapping CMR imaging was conducted on each patient. Instantaneous flow was acquired at discrete intervals within the cardiac cycle and ventricular function and volumes were evaluated. Five age-matched patients without aortic valve disease served as controls.

RESULTS

Conduit flow (as a percent of total cardiac output) was 65% ± 5%. Ejection fraction was unchanged compared with before AVB (50% ± 17% versus 57% ± 13%; p = 0.91). Ventricular volumes and cardiac indices were within normal limits and similar to those values in controls (cardiac index 2.9 ± 1.0 versus 2.3 L/min/m(2); p = 0.26; end-diastolic volume index 59 ± 17 mL versus 55 ± 20 mL; p = 0.66; end-systolic volume index, 25 ± 12 versus 25 ± 18 mL; p = 0.91; stroke volume index, 33 ± 11 versus 30 ± 6 mL; p = 0.57 for AVB and control patients, respectively). There was a small degree of retrograde blood flow in the descending aorta above the level of the conduit insertion (10% ± 8% of cardiac output).

CONCLUSIONS

Aortic valve bypass results in a predictable blood flow distribution between the native aorta and conduit and is associated with normal ventricular volumes and function.

Poor performances of EuroSCORE and CARE score for prediction of perioperative mortality in octogenarians undergoing aortic valve replacement for aortic stenosis

BACKGROUND AND OBJECTIVE

Although results of cardiac surgery are improving, octogenarians have a higher procedure-related mortality and more complications with increased length of stay in ICU. Consequently, careful evaluation of perioperative risk seems necessary. The aims of our study were to assess and compare the performances of EuroSCORE and CARE score in the prediction of perioperative mortality among octogenarians undergoing aortic valve replacement for aortic stenosis and to compare these predictive performances with those obtained in younger patients.

METHODS

This retrospective study included all consecutive patients undergoing cardiac surgery in our institution between November 2005 and December 2007. For each patient, risk assessment for mortality was performed using logistic EuroSCORE, additive EuroSCORE and CARE score. The main outcome measure was early postoperative mortality. Predictive performances of these scores were assessed by calibration and discrimination using goodness-of-fit test and area under the receiver operating characteristic curve, respectively.

RESULTS

During this 2-year period, we studied 2117 patients, among whom 134/211 octogenarians and 335/1906 nonoctogenarians underwent an aortic valve replacement for aortic stenosis. When considering patients with aortic stenosis, discrimination was poor in octogenarians and the difference from nonoctogenarians was significant for each score (0.58, 0.59 and 0.56 vs. 0.82, 0.81 and 0.77 for additive EuroSCORE, logistic EuroSCORE and CARE score in octogenarians and nonoctogenarians, respectively, P < 0.05). Moreover, in the whole cohort, logistic EuroSCORE significantly overestimated mortality among octogenarians.

CONCLUSION

Predictive performances of these scores are poor in octogenarians undergoing cardiac surgery, especially aortic valve replacement. Risk assessment and therapeutic decisions in octogenarians should not be made with these scoring systems alone.

Outcomes of minimally invasive valve surgery versus median sternotomy in patients age 75 years or greater

BACKGROUND

Advanced age is a major predictor of poor outcome in patients undergoing valve surgery. We hypothesized that elderly patients who underwent minimally invasive valve surgery for aortic or mitral valve disease would do better when compared with those undergoing the standard median sternotomy.

METHODS

We retrospectively reviewed 2,107 consecutive heart operations at our institution and identified 203 patients, age 75 years or greater, who underwent isolated mitral or aortic valve surgery. Outcomes of those who had minimally invasive valve surgery through a right minithoracotomy were compared with those who had a median sternotomy.

RESULTS

Of the 203 patients, 119 (59%) underwent a minimally invasive approach, while 84 (41%) had a median sternotomy. The median postoperative length of stay was 7 days (interquartile range [IQR] 6 to 10) versus 12 days (IQR 9 to 20), p less than 0.001, and intensive care unit length of stay was 52 hours (IQR 44 to 93) versus 119 hours (IQR 57 to 193), p less than 0.001 for minimally invasive and median sternotomy, respectively. In-hospital mortality was 2 (1.7%) versus 8 (9.5%, p=0.01 and composite postoperative morbidity and mortality occurred in 25 (21%) versus 38 (45.2%), p less than 0.001, in minimally invasive versus median sternotomy, respectively. The difference was driven by the following: a lower incidence of acute renal failure, 1 (0.8%) versus 14 (16.7%), p<0.001; prolonged intubation 23 (19.3%) versus 32 (38.1%), p=0.003; wound infections 1 (0.8%) versus 5 (6%), p=0.034; and death.

CONCLUSIONS

Minimally invasive surgery for isolated valve lesions in elderly patients yields a lower morbidity and mortality when compared with median sternotomy and should be considered when such individuals require valve surgery.

A new tool for the resection of aortic valves: In-vitro results for turning moments and forces using Nitinol cutting edges

The use of minimally invasive techniques for aortic valve replacement (AVR) may be limited for severely calcified and degenerated stenotic aortic valves. A quick resection leaving a defined geometry would be advantageous. Therefore, a new minimally invasive resection tool was developed, using rotating foldable cutting edges. This report describes the first experimental in-vitro results of measuring turning moment and forces during cutting of test specimens. Nitinol cutting edges were mounted on a simplified version of the resection instrument. The instrument shaft was combined with an exchangeable gear (1:3.71 vs. 1:5.0), and an exchangeable screw thread for accurate feed motion (0.35 mm or 0.5 mm) was implemented. Furthermore, the option of an added stabilisation body (SB) to prevent strut-torsion during cutting was tested. Tests were performed upon specially designed test specimens, imitating native calcified aortic valves. Resection was successful in all 60 samples (12 samples for each of the five configurations). Mean resection time ranged from 18.7+/-1.0 s (gear 1:3.71, screw thread 0.5, with SB) to 29.3+/-4.6 s (gear 1:5, screw thread 0.35, with SB), mean maximum turning moment ranged from 2.1+/-0.2 Nm (gear 1:3.71, screw thread 0.35, with SB) to 2.8+/-0.4 (gear 1:5, screw thread 0.35, with SB), mean maximum force from 36.0+/-11.3 N (gear 1:3.71, screw thread 0.35, with SB) to 56.3+/-10.5 N (gear 1:3.71, screw thread 0.5, without SB) and mean number of required rotations from 41.3+/-2.9 (gear 1:3.71, screw thread 0.5, with SB) to 59.1+/-3.7 (gear 1:3.71, screw thread 0.35, without SB). In summary, the positive influence of the stabilisation body could be shown. Combining the right parameters, it is possible to limit maximum cutting forces to F(max)<50 N and maximum turning moments to M(max)< 3.0 N.

Long-term outcomes after isolated aortic valve replacement in octogenarians: a modern perspective

BACKGROUND

With the recent advent of percutaneous valve therapy, an increased need for the evaluation of outcomes after open aortic valve replacement (AVR) in elderly patients is warranted. This study compares the short- and long-term survival outcomes of octogenarians after AVR with younger age groups in the modern surgical era.

METHODS

A retrospective review was performed on patients who underwent isolated, primary AVR from 1996 to 2006 at the Emory Healthcare Hospitals. Five-hundred fifteen patients were divided into three age groups: 60 to 69 (n = 206), 70 to 79 (n = 221), and 80 to 89 years of age (n = 88). Outcomes were compared among the age groups using logistic regression and analysis of variance techniques. Long-term survival between age groups was compared using the Cox proportional hazards model. Kaplan-Meier plots were used to determine survival rates.

RESULTS

The groups were similar with respect to in-hospital mortality (p = 0.66) and hospital length of stay (p = 0.08). Preoperative predictors of in-hospital mortality included stroke (odds ratio [OR] 5.36), chronic lung disease (OR 4.51), and renal failure (OR 1.39). As expected, age significantly impacted long-term survival (hazard ratio [HR] 1.06). Other predictors of long-term survival included stroke (HR 2.15), current smoker (HR 2.03), diabetes (HR 1.53), and renal failure (HR 1.4). The Kaplan-Meier estimate of median survival for octogenarians was 7.4 years.

CONCLUSIONS

In the modern era, octogenarians have acceptable short- and long-term results after open AVR. Comparisons of less invasive techniques for AVR should rely on outcomes based in the modern era and decisions regarding surgical intervention in patients requiring AVR should not be based on age alone.

Transcatheter Valve Repair and Replacement

There is significant interest in developing transcatheter therapy for valvular heart disease (VHD). Numerous devices have been developed for the percutaneous treatment of pulmonary and aortic stenosis as well as mitral regurgitation. Several of these devices have progressed to randomized clinical trials. These ongoing trials for aortic stenosis and mitral regurgitation will provide important insights into the durability of these therapies as well as the results following standard surgical repair. The field of transcatheter valve therapy is rapidly evolving, and this review aims to summarize the current status of the field.

Quality of Life after Mechanical vs. Biological Aortic Valve Replacement

To assess the quality of life after biological and mechanical aortic valve replacement, data of 136 patients were assessed retrospectively after 2 years of follow-up. Bioprostheses were implanted in 53 patients with a mean age of 74 years, and mechanical prostheses were used in 83 with a mean age of 64 years; there were 47 women and 89 men. Quality of life was evaluated using the Short Form 36-Item Health Survey questionnaire. Physical function scores were significantly better in patients with a mechanical prosthesis. Mental health indices were identical in both groups. Younger patients with mechanical valves and older patients with biological valves had significantly better item scores. In all age groups, men tended to have better scores than women, but a significant difference was noted only in the physical functioning index. The quality of life in patients with mechanical and biological valves was similar at 2 years postoperatively.