Real-Time Transthoracic Vector Flow Imaging of the Heart in Pediatric Patients.

In children with congenital heart defects, Doppler ultrasound is the standard, bedside imaging modality. However, precise characterization of blood flow is challenging due to angle-dependent and one-dimensional velocity estimation. Contrast agent free Vector Flow Imaging is a new ultrasound technology that enables angle-independent visualization of the detailed flow field. Two piglets, one with normal cardiac anatomy and one with congenital heart disease comprised of valvular pulmonary stenosis, a dilated main pulmonary artery, and an incomplete atrioventricular canal defect, were imaged transthoracically and epicardially using a BK Ultrasound bk5000 with built-in vector flow imaging and a 5MHz linear probe. Subsequently, two children, one with normal cardiac anatomy and one with congenital heart disease comprised of aortic valve stenosis and coarctation of the aorta were imaged transthoracically. Transthoracic two-dimensional echocardiography and vector flow imaging were readily performed in both animals and were limited only by the geometry of the porcine thorax. In addition, transthoracic vector flow imaging was successfully performed in both children, and abnormal flow secondary to cardiac anomalies was visible. Adequate penetration was obtained to a depth of 6.5 cm. Our group has previously demonstrated for the first time that transthoracic vector flow imaging echocardiography is feasible and practicable in pediatric-sized patients, and this paper describes examples of these concepts and in-depth comparisons with traditional imaging modalities. This paper demonstrates that commercially available vector flow imaging technology can be utilized in pediatric cardiac applications as a bedside transthoracic imaging modality, providing advanced detail of blood flow patterns within the cardiac chambers, across valves, and in the great arteries.

Should We Perform Carotid Doppler Screening Before Surgical or Transcatheter Aortic Valve Replacement?

BACKGROUND: Screening for internal carotid artery stenosis (ICAS) with Doppler ultrasound is commonly used before cardiovascular surgery. Nevertheless, the relationship between ICAS and procedure-related stroke in isolated aortic valve replacement is unclear. METHODS: We retrospectively reviewed patients with artery stenosis who underwent ICAS screening before surgical (SAVR) or transcatheter aortic valve replacement (TAVR) between January 2007 and August 2014. Logistic regression models were used to determine the relation between post-procedure stroke and total (sum of left and right ICAS) and maximal unilateral ICAS. Age, sex, history of atrial fibrillation, cerebrovascular disease and diabetes, left ventricular ejection fraction, and procedure type were considered as covariates. Two-subgroup analyses were performed in patients who underwent TAVR and SAVR, adjusting for procedure specific details. RESULTS: A total of 996 patients underwent ICAS screening before TAVR (n = 467) or SAVR (n = 529). The prevalence of at least ≥70% ICAS was 5.2% (n = 52) and incidence of 30-day stroke was 3.4% (n = 34). Eight patients who underwent carotid intervention before valve replacement and 6 patients with poor Doppler images were excluded from the final analysis. We found no statistically significant association between stroke and either the total or maximal unilateral ICAS for all patients (p = 0.13 and p = 0.39, respectively) or those undergoing TAVR (p = 0.27 and p = 0.63, respectively) or SAVR (p = 0.21 and p = 0.36, respectively). CONCLUSIONS: We found no statistically significant association between ICAS severity procedure-related stroke after aortic valve replacement. This suggests that universal carotid Doppler screening before isolated TAVR or SAVR is unnecessary.

Transcatheter Aortic Valve Replacement: Current Technology and Future Directions.

Transcatheter aortic valve replacement as an alternative to open surgical repair is rapidly becoming more used in high-risk patients with aortic stenosis. Transcatheter aortic valve replacement offers the benefit of being much less invasive than traditional surgical repair and has evolved as a therapeutic option for patients with prohibitive surgical risk or those deemed surgically inoperable. Nevertheless, despite its potential to mitigate risk in this frail population, it comes with its own unique set of complications. Technological advancements in valve structure, function, and delivery have and continue to attempt to minimize these risks. This review aims to summarize current advancements in transcatheter aortic valve replacement technology while also introducing areas of future direction in this exciting new field.

Impact of Preoperative Chronic Kidney Disease in 2,531 High-Risk and Inoperable Patients Undergoing Transcatheter Aortic Valve Replacement in the PARTNER Trial.

BACKGROUND: Although preoperative renal dysfunction (RD) is associated with increased mortality and morbidity after surgical aortic valve replacement, its impact on clinical outcomes after transcatheter aortic valve replacement (TAVR) is less defined. METHODS: TAVR patients in the PARTNER (Placement of Aortic Transcatheter Valves) trial with a calculable glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease equation were included. Patients were divided into three groups: GFR >60 mL/min (none/mild RD), GFR 31 to 60 mL/min (moderate RD), and GFR ≤30 mL/min (severe RD). Operative characteristics and clinical outcomes were analyzed. Cox regression models were used to determine multivariable predictors of 1-year all-cause mortality. RESULTS: A total of 2,531 inoperable or high surgical risk patients from the PARTNER trial and continued access registries had a calculable GFR level: 767 (30%) had normal renal function or mild RD, 1,473 (58%) had moderate RD, and 291 (12%) presented with severe RD. The mean Society of Thoracic Surgeons Predicted Risk of Mortality for the cohort was 11.5%, and it was highest in those with severe RD (13.8%). Patients with severe RD were more often women with a higher prevalence of diabetes. Patients with severe RD had the highest incidence of 30-day and 1-year all-cause mortality and rehospitalization. The 30-day rate of death from any cause was 10.7% in the severe RD group versus 6.0% in the moderate and mild RD groups (p = 0.01). The 1-year rate of death from any cause was 34.4% in the severe RD group versus 21.5% in the moderate RD and 20.8% in the none/mild RD groups (adjusted hazard ratio [HR] 2.24, p < 0.0001 for severe versus none/mild; adjusted HR 1.14, p = 0.24 for severe versus moderate). Other significant predictors of 1-year all-cause mortality included lower body mass index, frailty, the transapical approach, a lower ejection fraction, oxygen-dependent chronic obstructive pulmonary disease, liver disease, and male sex. CONCLUSIONS: Preoperative severe RD is a significant predictor for 1-year mortality in TAVR patients. Careful risk stratification by the heart team is required in patients with severe preprocedural RD.

Endothelial cell dysfunction as a novel therapeutic target in atherosclerosis.

INTRODUCTION: Dysfunction of vessel endothelium is the first step in a complex and multi-faceted process that eventually leads to initiation of the plaque, formation of atherosclerotic lesions and their complications. The extremely fine-regulated endothelium is the gatekeeper of vascular health, and has been the target of a substantial amount of research. AREAS COVERED: This review examines some of the most common associations between therapies of cardiovascular disease and the endothelium, and summarizes the direction of research that may set the stage for one or more interventions targeted to repair damaged and/or dysfunctional endothelium. Expert commentary: Routine treatment of cardiovascular disease has frequently been shown to have a positive effect on the vascular endothelium. The big question - whether the impact is due to a direct pharmacological effect or whether the function of the endothelium improves as a result of a general improvement in the underlying disease state, is still largely unanswered.

Does a Higher Society of Thoracic Surgeons Score Predict Outcomes in Transfemoral and Alternative Access Transcatheter Aortic Valve Replacement?

BACKGROUND: Nontransfemoral (non-TF) transcatheter aortic valve replacement (TAVR) is often associated with worse outcomes than TF TAVR. We investigated the relationship between increasing Society of Thoracic Surgeons (STS) predicted risk of mortality (PROM) score and observed mortality and morbidity in TF and non-TF TAVR groups. METHODS: We reviewed 595 patients undergoing TAVR at Emory Healthcare between 2007 and 2014. Clinical outcomes were reported for 337 TF patients (57%) and 258 non-TF patients (43%). We created 3 STS PROM score subgroups: <8%, 8%-15%, and >15%. A composite outcome of postoperative events was defined as death, stroke, renal failure, vascular complications, or new pacemaker implantation. RESULTS: TF patients were older (82.4 ± 8.0 vs 80.8 ± 8.7 years, p = 0.02), whereas the STS PROM was higher in non-TF patients (10.5% ± 5.3% vs 11.7% ± 5.7%, p = 0.01). Observed/expected mortality was less than 1.0 in all groups. The rate of the composite outcome did not differ between STS PROM subgroups in TF (p = 0.68) or non-TF TAVR (p = 0.27). One-year mortality was higher for patients with STS PROM >8% in the non-TF group; however, this difference was not observed in TF patients (p = 0.40). CONCLUSIONS: As expected, non-TF patients were at a higher risk than TF patients for procedural morbidity and death. Although no differences were observed in 30-day deaths or morbidity in different STS PROM subgroups, those undergoing non-TF TAVR at a higher STS PROM (>8%) had higher 1-year mortality. When applicable, TF TAVR remains the procedure of choice in high- or extreme-risk patients undergoing TAVR.

Intensive Glycemic Control in Cardiac Surgery.

Hyperglycemia has been found to be associated with increased morbidity and mortality in surgical patients, yet, the optimal glucose management strategy during the perioperative setting remains undetermined. While much has been published about hyperglycemia and cardiac surgery, most studies have used widely varying definitions of hyperglycemia, methods of insulin administration, and the timing of therapy. This has only allowed investigators to make general conclusions in this challenging clinical scenario. This review will introduce the basic pathophysiology of hyperglycemia in the cardiac surgery setting, describe the main clinical consequences of operative hyperglycemia, and take the reader through the published material of intensive and conservative glucose management. Overall, it seems that intensive control has modest benefits with adverse effects often outweighing these advantages. However, some studies have indicated differing results for certain patient subgroups, such as non-diabetics with acute operative hyperglycemia. Future studies should focus on distinguishing which patient populations, if any, would optimally benefit from intensive insulin therapy.

Transcatheter Aortic Valve Replacement Results in Improvement of Pulmonary Function in Patients With Severe Aortic Stenosis.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) has been identified as a risk factor for morbidity and mortality after transcatheter aortic valve replacement (TAVR). We hypothesized that a portion of pulmonary dysfunction in patients with severe aortic stenosis may be of cardiac origin, and has potential to improve after TAVR. METHODS: A retrospective analysis was made of consecutive TAVR patients from April 2008 to October 2014. Of patients who had pulmonary function testing and serum B-type natriuretic peptide data available before and after TAVR, 58 were found to have COPD (26 mild, 14 moderate, and 18 severe). Baseline variables and operative outcomes were explored along with changes in pulmonary function. Multiple regression analyses were performed to adjust for preoperative left ventricular ejection fraction and glomerular filtration rate. RESULTS: Comparison of pulmonary function testing before and after the procedure among all COPD categories showed a 10% improvement in forced vital capacity (95% confidence interval: 4% to 17%) and a 12% improvement in forced expiratory volume in 1 second (95% confidence interval: 6% to 19%). There was a 29% decrease in B-type natriuretic peptide after TAVR (95% confidence interval: -40% to -16%). An improvement of at least one COPD severity category was observed in 27% of patients with mild COPD, 64% of patients with moderate COPD, and 50% of patients with severe COPD. There was no 30-day mortality in any patient group. CONCLUSIONS: In patients with severe aortic stenosis, TAVR is associated with a significant improvement of pulmonary function and B-type natriuretic peptide. After TAVR, the reduction in COPD severity was most evident in patients with moderate and severe pulmonary dysfunction.

Minimalist transcatheter aortic valve replacement: The new standard for surgeons and cardiologists using transfemoral access?

BACKGROUND: A minimalist approach for transcatheter aortic valve replacement (MA-TAVR) utilizing transfemoral access under conscious sedation and transthoracic echocardiography is increasing in popularity. This relatively novel technique may necessitate a learning period to achieve proficiency in performing a successful and safe procedure. This report evaluates our MA-TAVR cohort with specific characterization between our early, midterm, and recent experience. METHODS: We retrospectively reviewed 151 consecutive patients who underwent MA-TAVR with surgeons and interventionists equally as primary operator at Emory University between May 2012 and July 2014. Our institution had performed 300 TAVR procedures before implementation of MA-TAVR. Patient characteristics and early outcomes were compared using Valve Academic Research Consortium 2 definitions among 3 groups: group 1 included the first 50 patients, group 2 included patients 51 to 100, and group 3 included patients 101 to 151. RESULTS: Median age for all patients was 84 years and similar among groups. The majority of patients were men (56%) and the median ejection fraction for all patients was 55% (interquartile range, 38.0%-60.0%). The majority of patients were high-risk surgical candidates with a median Society of Thoracic Surgeons Predicted Risk of Mortality of 10.0% and similar among groups. The overall major stroke rate was 3.3%, major vascular complications occurred in 3% of patients, and greater-than-mild paravalvular leak rate was 7%. In-hospital mortality and morbidity were similar among all 3 groups. CONCLUSIONS: In a high-volume TAVR center, transition to MA-TAVR is feasible with acceptable outcomes and a diminutive procedural learning curve. We advocate for TAVR centers to actively pursue the minimalist technique with equal representation by cardiologists and surgeons.

Outcomes in Nonagenarians Undergoing Transcatheter Aortic Valve Replacement in the PARTNER-I Trial.

BACKGROUND: This study describes short-term and mid-term outcomes of nonagenarian patients undergoing transfemoral or transapical transcatheter aortic valve replacement (TAVR) in the Placement of Aortic Transcatheter Valve (PARTNER)-I trial. METHODS: From April 2007 to February 2012, 531 nonagenarians, mean age 93 ± 2.1 years, underwent TAVR with a balloon-expandable prosthesis in the PARTNER-I trial: 329 through transfemoral (TF-TAVR) and 202 transapical (TA-TAVR) access. Clinical events were adjudicated and echocardiographic results analyzed in a core laboratory. Quality of life (QoL) data were obtained up to 1 year post-TAVR. Time-varying all-cause mortality was referenced to that of an age-sex-race-matched US population. RESULTS: For TF-TAVR, post-procedure 30-day stroke risk was 3.6%; major adverse events occurred in 35% of patients; 30-day paravalvular leak was greater than moderate in 1.4%; median post-procedure length of stay (LOS) was 5 days. Thirty-day mortality was 4.0% and 3-year mortality 48% (44% for the matched population). By 6 months, most QoL measures had stabilized at a level considerably better than baseline, with Kansas City Cardiomyopathy Questionnaire (KCCQ) 72 ± 21. For TA-TAVR, post-procedure 30-day stroke risk was 2.0%; major adverse events 32%; 30-day paravalvular leak was greater than moderate in 0.61%; and median post-procedure LOS was 8 days. Thirty-day mortality was 12% and 3-year mortality 54% (42% for the matched population); KCCQ was 73 ± 23. CONCLUSIONS: A TAVR can be performed in nonagenarians with acceptable short- and mid-term outcomes. Although TF- and TA-TAVR outcomes are not directly comparable, TA-TAVR appears to carry a higher risk of early death without a difference in intermediate-term mortality. Age alone should not preclude referral for TAVR in nonagenarians.

Transapical and Transaortic Transcatheter Aortic Valve Replacement in the United States.

BACKGROUND: When transcatheter aortic valve replacement (TAVR) cannot be carried out through transfemoral access, alternative access TAVR is indicated. The purpose of this study was to explore inhospital and 1-year outcomes of patients undergoing alternative access TAVR through the transapical (TA) or transaortic (TAo) techniques in the United States. METHODS: Clinical records of 4,953 patients undergoing TA (n = 4,085) or TAo (n = 868) TAVR from 2011 to 2014 in The Society of Thoracic Surgeons (STS)/American College of Cardiology Transcatheter Valve Therapy Registry were linked to Centers for Medicare and Medicaid Services hospital claims. Inhospital and 1-year clinical outcomes were stratified by operative risk; and the risk-adjusted association between access route and mortality, stroke, and heart failure repeat hospitalization was explored. RESULTS: Mean age for all patients was 82.8 ± 6.8 years. The median STS predicted risk of mortality was significantly higher among patients undergoing TAo (8.8 versus 7.4, p < 0.001). When compared with TA, TAo was associated with an increased risk of unadjusted 30-day mortality (10.3% versus 8.8%) and 1-year mortality (30.3% versus 25.6%, p = 0.006). There were no significant differences between TAo and TA for inhospital stroke rate (2.2%), major vascular complications (0.3%), and 1-year heart failure rehospitalizations (15.7%). Examination of high-risk and inoperable subgroups showed that 1-year mortality was significantly higher for TAo patients classified as inoperable (p = 0.012). CONCLUSIONS: Patients undergoing TAo TAVR are older, more likely female, and have significantly higher STS predicted risk of mortality scores than patients operated on by TA access. There were no risk-adjusted differences between TA and TAo access in mortality, stroke, or readmission rates as long as 1 year after TAVR.

Outcomes for Transcatheter Aortic Valve Replacement in Nonagenarians.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) may offer extreme-aged patients a treatment alternative to surgical aortic valve replacement (SAVR). The objective of this study was to describe outcomes of TAVR in nonagenarians using transfemoral and alternative access techniques. METHODS: In a retrospective review, we found 95 nonagenarians who underwent TAVR from September 2007 through February 2014 at Emory University using a balloon expandable valve: transfemoral (n = 66), transapical (n = 14), transaortic (n = 14), and transcarotid (n = 1). Morbidity and 30-day and midterm mortality were assessed. Kaplan-Meier plots were used to determine midterm survival rates. RESULTS: The mean age of the patients was 91.8 ± 1.8 years, and 49 (52%) were female. Postoperative morbidity included 1 patient (1%) each with stroke, myocardial infarction, pneumonia, and renal failure. The mean postoperative length of stay was 6.8 ± 5.1 days for all patients. Overall 30-day mortality was 3.2%, much less than The Society of Thoracic Surgeons predicted risk of mortality of 14.5% ± 7.3%. There were no deaths in the transfemoral patients, but there were 2 transapical deaths (14.3%) and 1 transaortic death (7.1%). The Kaplan-Meier estimate of median survival was 2.6 years. CONCLUSIONS: Extreme-aged nonagenarian patients may have excellent outcomes from TAVR at 30-day and midterm follow-up. Alternative access TAVR is associated with higher morbidity and mortality than transfemoral TAVR. Referral for TAVR of nonagenarians should not be precluded based on age alone.

Performance monitoring of the arterial switch operation: a moving target.

OBJECTIVES: Twenty years ago our institution published an analysis of a cluster of failures associated with the arterial switch operation (ASO). The concept of 'near miss' was explored to detect warning signs of suboptimal performance. The aim of the current study was to review the parameters best suited to monitoring early ASO outcomes in the modern setting and re-examine the concept of near misses as failure equivalents. METHODS: All ASOs performed in our institution between 1983 and 2012 were reviewed. The experience was divided into three eras (1983-92, 1993-2002 and 2003-12). The cumulative sum graphic for sequential monitoring was used for early mortality. The need to re-establish cardiopulmonary bypass (CPB), CPB time >240 min and extracorporeal membrane oxygenation (ECMO) were explored as variables of near misses. RESULTS: The cohort consisted of 606 patients. The 30-day mortality rate was 23% (n = 29) in Era 1, 6% (n = 14) in Era 2 and 1% (n = 3) in Era 3. There were further 4, 8 and 6 deaths between 30 and 90 days in the three eras, respectively. In Era 3, the majority of deaths occurred between 30 and 90 days. In the current era, ECMO and CPB time >240 min as a marker of near miss was associated with an increased risk of death both within 30 days and 90 days after ASO. CONCLUSIONS: The 30-day outcomes of ASO have significantly improved over the last 30 years. As life-saving mechanical support after surgery has been implemented more often, an extended 90-day window of reporting can offer a more realistic outcome indicator of performance.

High-risk patients with inoperative aortic stenosis: use of transapical, transaortic, and transcarotid techniques.

BACKGROUND: Patient characteristics and procedural outcomes from nontransfemoral (non-TF) transcatheter aortic valve replacement (TAVR) in high-risk or inoperable patients with aortic stenosis have been incompletely reported. The purpose of this study was to compare outcomes with non-TF TAVR access techniques including transapical (TA), transaortic (TAo), and transcarotid (TC) TAVR with a balloon-expandable valve. METHODS: A retrospective review was performed of all patients undergoing TA, TAo, and TC TAVR from 2007 to 2013 at Emory University. Preoperative risk factors and postoperative outcomes were evaluated using Valve Academic Research Consortium-2 definitions. RESULTS: Of 469 patients undergoing TAVR during that period at our institution, 139 underwent TA TAVR, 35 had Tao TAVR, and 11 had TC TAVR. Patients undergoing TC TAVR were younger than those undergoing TA TAVR and TAo TAVR (mean ages: TC, 68.9 ± 23.6 years; TA, 81.3 ± 7.7 years; Tao, 83.8 ± 8.3 years; p = 0.017). Most patients undergoing TAo TAVR were women (82.9%), whereas patients undergoing TA TAVR were more likely to be men (62.6%). Slightly more than half of patients undergoing TA TAVR (54.7%) and TC (54.6%) TAVR had undergone previous coronary artery bypass grafting (CABG), whereas no patients underwent TAo TAVR (0%). There was no preoperative difference in ejection fraction, New York Heart Association classification, significant chronic obstructive pulmonary disease, and The Society of Thoracic Surgeons predicted risk of mortality between TA TAVR, Tao TAVR, and TC TAVR, respectively. Average postoperative length of stay was 9 to 11 days and was similar among groups (p = 0.22). There were 13 (9.4%) TA TAVR operative deaths and 4 (11.4%) operative deaths in the TAo TAVR group. There were no deaths in the TC TAVR group. CONCLUSIONS: In high-risk and inoperable patients who are not candidates for TF TAVR, careful selection of alternative access options can lead to excellent and comparable postoperative outcomes.

Nontransfemoral Approaches to Transcatheter Aortic Valve Replacement.

Transcatheter aortic valve replacement (TAVR) is noninferior to surgical aortic valve replacement in patients with high operative risk and superior to medical treatment in patients deemed unsuitable for surgical intervention. However, up to 30% to 50% of patients screened for this intervention are not candidates for TAVR via the preferred transfemoral route because of severe peripheral arterial disease. Alternative access routes must be considered and include the transapical, transaortic, transsubclavian, and transcarotid approaches. The use of alternative access is predicated on appropriate patient selection as determined by a dedicated multispecialty heart valve team and can lead to excellent outcomes.