Blood versus crystalloid cardioplegia during triple valve surgery: A single center experience.

BACKGROUND: The efficacy of different cardioplegia solutions on outcomes of complex cardiac operations such as triple valve surgery (TVS) is scarce. Here we compared the outcomes in TVS patients receiving either crystalloid (Bretschneider) or blood (Calafiore) cardioplegia. METHODS: Screening of our institutional database with prospectively entered data identified 471 consecutive patients (mean age 70.3 ± 9.2 years; 50.9% male), who underwent TVS (replacement or repair of aortic, mitral and tricuspid valve) between December 1994 and January 2013. In 277 patients, cardiac arrest was induced with HTK-Bretschneider solution (HTK, n = 277, 58.8%), whereas 194 received cold blood cardioplegia (BCP) according to Calafiore (n = 194, 41.2%). Comparisons of perioperative and follow up outcomes were made between cardioplegia groups. RESULTS: Preoperative patient characteristics and comorbidities were equally balanced between groups. 30-days mortality was similar between groups (HTK: 16.2%; BCP: 18.2%; p = 0.619). Incidence of the cumulative endpoint (30days mortality, myocardial infarction (MI), arrhythmia, low cardiac output syndrome or need for permanent pacemaker implantation) was also comparable (HTK: 47.6%; BCP: 54.8%, p = 0.149). In patients with reduced left ventricular ejection fraction (LVEF <40%), 30days mortality was higher in the HTK group (HTK 18/71 22.5%; BCP 5/50 10%; p = 0.037). Five-year survival was similar between groups (52 ± 6% for HTK and 55 ± 5% for BCP patients). In-Hospital mortality was best predicted by length of surgery and reperfusion ratio. Decreased age, shorter bypass time, preserved LVEF and concomitant surgical procedures have been found to be protective from long-term mortality. CONCLUSIONS: Myocardial protection with HTK shows equivalent outcomes compared to BCP during TVS. Patients with reduced left ventricular function may benefit from BCP during TVS.

Cyclosporine A-enhanced cardioplegia preserves mitochondrial basal respiration after ischemic arrest.

BACKGROUND: Mitochondrial permeability transition pore (mPTP) opening plays a crucial role in cell death during ischemia-reperfusion injury (IRI). Cyclosporine A (CsA) inhibits mPTP opening. This study aimed to investigate the effects of CsA treatment during cardioplegia on the mitochondrial function and cardiac IRI. METHODS: Landrace pigs (52.9 ± 3.7 kg) were subjected to midline sternotomy, cardiopulmonary bypass at 34°C and 90 minutes of cardiac arrest. They received either a single shot of standard 4°C cold histidine-tryptophan-α-ketoglutarate (HTK)-Bretschneider solution (n = 11) or HTK-Bretschneider plus 1.2 mg/L CsA (histidine-tryptophan-α-ketoglutarate plus cyclosporine A (HTK/CsA); n = 11). During reperfusion global left-ventricular function was assessed and myocardial biopsies were harvested at baseline, during ischemia and 45 minutes following reperfusion. High-resolution respirometry and hydrogen peroxide production were measured. Immunohistochemical stainings for apoptosis-inducing factor and hypoxia-inducible factor-1α as well as a flow cytometry-based JC-1 mitochondrial membrane potential assay were performed. RESULTS: Hemodynamic parameters were comparable between both groups. The cytochrome C release (HTK: 930.3 ± 804.4 pg/mg, HTK/CsA: 699.7 ± 394.0 pg/mg, p = 0.457) as well as PGC1α content (HTK: 66.7%, HTK/CsA: 33.3%, p = 0.284) was lower in the HTK/CsA group. Respiratory measurements revealed that the oxygen flux under basal respiration was higher in the HTK/CsA group (8.2 ± 1.3 pmol·O2·s-1·mg-1·ww) than in the HTK group (3.8 ± 1.4 pmol·O2·s-1·mg-1·ww, p = 0.045). There were no significant differences regarding histological surrogates of apoptosis and necrosis. CONCLUSIONS: Supplementing cardioplegic solutions with CsA enhances the basal mitochondrial respiration thereby exerting a cardioprotective effect and diminishing IRI-induced damage. CsA seems to preserve mitochondrial function via non-ROS related pathways.

Impact of Custodiol-N cardioplegia on acute kidney injury after cardiopulmonary bypass.

Myocardial protection during cardiopulmonary bypass (CPB) can be achieved using cardioplegic solutions. Although, acute kidney injury (AKI) is a common complication following CPB, the effects of cardioplegic solutions on AKI have rarely been investigated. Within this study, the effects of the cardioplegic solutions histidine-tryptophan-ketoglutarate (HTK; Custodiol) and HTK-N (Custodiol-N) on AKI in a large animal model were compared. Therefore, Landrace pigs underwent median sternotomy, CPB at 34°C, 90 minutes of cardiac arrest and 120 minutes of reperfusion. Animals were randomized for single-shot cardioplegia with either HTK (n = 10) or HTK-N (n = 10). Renal biopsies and sera were analyzed to determine AKI biomarkers and apoptosis. Compared to HTK, HTK-N induced a decreased extent of proximal tubule swelling (48.3 ± 1.6 µm vs 52.3 ± 1.1 µm, P = .05) and decreased cytochrome c release (0.26 ± 0.04 vs 0.46 ± 0.08, P = .04) without reaching statistical significance due to Bonferroni correction. Comparing baseline and postreperfusion levels, the hemoglobin (Hb) and blood calcium levels were lower in HTK-N (Hbbaseline : 6.0 ± 0.6 mmol/L, Hbreperfusion : 6.2 ± 0.7 mmol/L, P = .12; Ca2+baseline : 1.36 ± 0.05 mmol/L, Ca2+reperfusion : 1.28 ± 0.05 mmol/L, P = .16) compared to the HTK group (Hbbaseline : 5.9 ± 0.4 mmol/L, Hbreperfusion : 4.7 ± 0.8 mmol/L, P < .01; Ca2+baseline : 1.34 ± 0.07 mmol/L, Ca2+reperfusion : 1.24 ± 0.06 mmol/L, P < .01). The present study showed that HTK-N could positively affect the kidney during CPB. Hb and calcium levels were stabilized. A statistical trend was found showing that AKI-related proximal tubule swelling and cytochrome c release were diminished.

Preoperative Predictors and Outcome of Triple Valve Surgery in 487 Consecutive Patients.

Background Triple valve surgery (TVS) is associated with an elevated risk for operative mortality and thus remains a surgical challenge. We report our experience and results of TVS procedures, especially with respect to identification of preoperative risk factors, to improve patient selection. Methods Between December 1994 and January 2013, 487 consecutive patients (240 male, 247 female) underwent TVS at the Heart Center Leipzig, University of Leipzig. The data were prospectively collected and retrospectively analyzed. Univariate and multivariable regression analyses were performed to identify risk factors. Results The 30-day mortality was 16.1% and the long-term survival at 1 year and 5 years was 71.8% and 54.6%, respectively. Multivariable logistic regression analysis identified previous myocardial infarction to be the only significant predictor for early mortality. Age, New York Heart Association functional class IV, previous myocardial infarction, dialysis, and liver dysfunction were identified as preoperative predictors for late mortality. Furthermore, an increase of operative risk, given for each year, was observed during the study period. In contrast, 30-day mortality decreased during the observation time. Conclusion TVS is associated with a high surgical risk. Long-term survival is decreased, but acceptable for these high-risk patients. The series demonstrates that increasing surgical risk, age, and comorbidities are the future challenges in TVS.

Longevity after aortic root replacement: is the mechanically valved conduit really the gold standard for quinquagenarians?

BACKGROUND: The choice of the best conduit for root/ascending disease and its impact on longevity remain controversial in quinquagenarians. METHODS AND RESULTS: A total of 205 patients (men=155) between 50 and 60 years (mean, 55.7 ± 2.9 years) received either a stentless porcine xenoroot (n=78) or a mechanically valved composite prosthesis (n=127) between February 1998 and July 2011. Of these, 166 patients underwent root replacement for aneurysmal disease (porcine: 39% [n=65]; mechanical: 61% [n=101]; P=0.5), 25 for acute type A aortic dissection (porcine: 32% [n=8]; mechanical: 68% [n=17]; P=0.51), and 14 for endocarditis/iatrogenic injury involving the aortic root (6.4% [n=5] versus 7.1% [n=9]; P=1.0). The predominant aortic valve pathology was stenosis in 19% (n=38), regurgitation in 50% (n=102), combined valvular dysfunction in 26% (n=54), and normal aortic valve function in 5% (n=11). Concomitant procedures included coronary artery bypass grafting (13%), mitral valve repair (7%), and partial/complete arch replacement (12%/4%), with no significant differences between porcine and mechanical root replacement. Overall hospital mortality was 7.3%, with no difference between the 2 types of valve prostheses (7.7% for porcine and 7.1% for mechanical root replacement; P=1.0). Follow-up averaged 5.4 ± 3.7 years (1096 patient-years) and was 100% complete. Freedom from aorta-related reoperation at 12 years was not statistically different between the groups (porcine: 94.9% versus mechanical: 96.1%; P=0.73). Survival was equivalent between both groups, with a 5-year survival of 86 ± 3% (porcine: 88 ± 4%; mechanical: 85 ± 3%; P=0.96) and a 10-year survival of 76% (porcine: 80 ± 7%; mechanical: 75 ± 5%; P=0.84). The linearized mortality rate was 3.1%/patient-year (porcine: 2.9%/patient-year; mechanical: 3.2%/patient-year). CONCLUSIONS: In quinquagenerians, long-term survival after stentless porcine xenograft aortic root replacement is equivalent to that after a mechanical Bentall procedure. These results bring into question the predominance of mechanical composite conduits for root replacement in quinquagenerians, particularly in the current era of transcatheter valve-in-valve procedures for structural valve deterioration.

Comparison of modified Del Nido and Custodiol® cardioplegia in minimally invasive mitral valve surgery.

OBJECTIVES: In this study, we evaluated if modified Del Nido cardioplegia delivers comparable cardiac protection in comparison to Custodiol® in patients undergoing isolated minimally invasive mitral valve repair. METHODS: From January 2018 to October 2021, all patients undergoing non-emergent isolated minimally invasive mitral valve repair were included in this study. The cardioplegia was chosen at the surgeons' discretion. The primary end points of this study were peak postoperative cardiac enzyme levels. Secondary end points were in-hospital mortality, hospital stay, occurrence of cardiac arrhythmias, pacemaker implantations, postoperative lactate and sodium levels and postoperative incidence of renal failure requiring dialysis. RESULTS: A total of 355 patients were included in this study. The mean age of patients was 57. After propensity score matching, a total of 156 pairs were identified. There was no difference in cross-clamp time between both groups. Postoperative creatine kinase levels were higher in patients receiving Custodiol on the 1st and 2nd postoperative days. Creatine kinase isoenzyme MB levels were higher in patients receiving Custodiol on the 2nd postoperative day (0.5 ± 0.2 vs 0.4 ± 0.1 µmol/l s; P < 0.001). Postoperative Troponin T concentrations were similar between both groups. Maximum lactate concentrations were higher in patients receiving Custodiol on the day of surgery (2.4 ± 1.9 vs 2.0 ± 1.1 mmol/l; P = 0.04). The overall hospital stay was longer in patients receiving Del Nido cardioplegia (10.6 ± 3.2 vs 8 ± 4.1 days; P < 0.01). CONCLUSIONS: Modified Del Nido cardioplegia based on Ionosteril® solution offers equivalent protection compared to Custodiol for isolated minimally invasive mitral valve repair.

Incidence and outcomes of emergency intraprocedural surgical conversion during transcatheter aortic valve implantation: Insights from a large tertiary care centre.

OBJECTIVE: During a transcatheter aortic valve implant (TAVI) procedure, intraprocedural complications that are manageable only by conversion to emergency open-heart surgery (E-OHS) occasionally occur. Contemporary data on the incidence and outcome of TAVI patients undergoing E-OHS are scarce. This study aimed to evaluate early and midterm outcomes following E-OHS of patients undergoing TAVI in a large tertiary care centre with immediate surgical backup availability for all TAVI procedures over a 15-year period. METHODS: Data from all patients undergoing transfemoral TAVI between 2006 and 2020 at the Heart Centre Leipzig were analysed. The study time was divided into 3 periods: 2006-2010 (P1), 2011-2015 (P2) and 2016-2020 (P3). Patients were grouped according to their surgical risk (high risk: EuroSCORE II ≥ 6%; low/intermediate risk: EuroSCORE II <6%). Primary outcomes were intraprocedural and in-hospital death and 1-year survival. RESULTS: During the study period, a total of 6903 patients underwent transfemoral TAVI. Among them, 74 (1.1%) required E-OHS [high risk, n = 66 (89.2%); low/intermediate risk, n = 8 (10.8%)]. The rate of patients requiring E-OHS was 3.5% (20/577 patients), 1.8% (35/1967 patients) and 0.4% (19/4359 patients) in study periods P1 to P3, respectively (P < 0.001). The proportion of patients who had E-OHS who were low/intermediate risk increased considerably over time (P1:0%; P28.6%; P3:26.3%; P = 0.077). Intraprocedural deaths occurred in 10 patients (13.5%), all of whom were high-risk. In-hospital mortality was 62.1% in high-risk patients and 12.5% in low/intermediate risk patients (P = 0.007). One-year survival was 37.8% in all patients undergoing E-OHS, 31.8% in high-risk patients and 87.5% in low/intermediate risk patients (log-rank P = 0.002). CONCLUSIONS: In-hospital and 1-year survival rates following E-OHS are higher in low/intermediate risk than in high-risk patients undergoing TAVI. An on-site cardiac surgical department with immediately available E-OHS capabilities is an important component of the TAVI team.

Direct transaortic transcather valve-in-valve implantation into a mechanical aortic valve prosthesis during left ventricular assist device implantation: description of a surgical technique.

The presence of a mechanical aortic valve prosthesis is considered a relative contraindication for left ventricular assist device implantation (LVAD) due to the occurrence of thromboembolic events. Five patients were operated on for LVAD implantation with status post mechanical aortic valve implantation (n = 3 with status post Bentall procedure). After removal of the leaflets, a transcatheter balloon-expandable valve was placed within the mechanical ring in all patients. Three patients were discharged from hospital with a maximum follow-up of 3.3 years. Transaortic transcatheter valve implantation into a mechanical aortic valve during LVAD implantation is a feasible option. It reduces operative times and might also prevent thromboembolic events.

Early- and mid-term outcomes following redo surgical aortic valve replacement in patients with previous transcatheter aortic valve implantation.

OBJECTIVES: The aim of this study was to analyse the early- and mid-term outcomes after redo surgical aortic valve replacement (SAVR) in patients with previous transcatheter aortic valve implantation (TAVI). METHODS: Retrospective single-centre analysis of early- and mid-term outcomes following redo SAVR in patients with previous TAVI between 2013 and 2020. Primary outcomes were in-hospital mortality and mid-term survival. RESULTS: During the study period, a total of 5756 patients underwent TAVI. Among them, 28 (0.5%) patients required redo SAVR after TAVI. During periods 2013-2016 and 2017-2020, 4/2184 (0.2%) patients and 24/3572 (0.7%) patients required SAVR after TAVI, respectively. The median logistic EuroSCORE was significantly higher at the time of SAVR than at the time of the index TAVI (5.9% vs 11.6%; P < 0.001). The median elapsed time between TAVI and redo SAVR was 7 months (3.5-14 months). Infective endocarditis (IE) was the most frequent indication for surgery [19 (67.8%) patients]. A total of 11 (39.3%) patients underwent isolated SAVR and 17 (60.7%) SAVR + additional cardiac surgical procedures. The overall in-hospital mortality was 14.3% (4/28). In-hospital mortality was 15.8% (3/19) among IE patients and 11.1% (1/9) among non-IE patients (P = 0.7). Overall estimated survival was 66.5%, 59.9% and 48.0% at 12, 18 and 24 months, respectively. Patients with IE showed a trend towards a lower estimated mid-term survival compared to non-IE patients [41.6% (95% confidence interval: 22.0-78.0%) vs 58.3% (95% confidence interval: 30.0-100%) survival at 24 months (P = 0.3)]. CONCLUSIONS: SAVR can be successfully performed in patients with prior TAVI despite the increased surgical risk and technical difficulty. IE is associated with decreased mid-term survival.

Relevance and Recommendations for the Application of Cardioplegic Solutions in Cardiopulmonary Bypass Surgery in Pigs.

Cardioplegic solutions play a major role in cardiac surgery due to the fact that they create a silent operating field and protect the myocardium against ischemia and reperfusion injury. For studies on cardioplegic solutions, it is important to compare their effects and to have a valid platform for preclinical testing of new cardioplegic solutions and their additives. Due to the strong anatomical and physiological cardiovascular similarities between pigs and humans, porcine models are suitable for investigating the effects of cardioplegic solutions. This review provides an overview of the results of the application of cardioplegic solutions in adult or pediatric pig models over the past 25 years. The advantages, disadvantages, limitations, and refinement strategies of these models are discussed.

Durability and clinical experience using a bovine pericardial prosthetic aortic valve.

OBJECTIVES: To report the implant experience and long-term outcomes from a large tertiary care referral center on surgical aortic valve replacement (SAVR) with a contemporary stented pericardial bioprosthesis with anticalcification treatment. METHODS: Patients underwent SAVR using the Trifecta valve at a single institution. Endpoints included procedural outcomes, adverse events, prosthesis-patient mismatch (PPM), long-term survival, and valve durability. Follow-up included 30-day, 6-month, and annual assessments. Treatment for structural valve deterioration (SVD) included surgical explant and valve-in-valve (V-in-V) transcatheter aortic valve implantation (TAVI). RESULTS: SAVR was performed in 1241 patients (median age, 73.5 ± 6.4 years; 54% male; median logistic EuroSCORE, 7.8) with concomitant procedures in 713 cases (57.5%). Intraprocedural mortality was 1.4%, and 30-day mortality was 6.0%. At hospital discharge, 68 patients (5.5%) had moderate PPM, and no patients had severe PPM. Adverse events included cardiac arrhythmias (44.7%, mostly atrial fibrillation), respiratory failure (22.9%), acute renal failure requiring temporary renal replacement therapy (12.9%), and low cardiac output syndrome (3.3%). Follow-up data were available over a total of 5469 patient-years (median duration of follow-up, 4.7 years). Freedom at 8 years from all-cause mortality, valve-related mortality, reoperation for SVD (redo SAVR or V-in-V TAVI), and endocarditis were 78.4%, 98.0%, 93.3%, and 96.5%, respectively. Of the 30 patients with SVD, 17 were treated by V-in-V TAVI and 13 underwent surgical explant. CONCLUSIONS: Outcomes from this large single-center cohort at increased surgical risk demonstrate excellent long-term durability of the Trifecta valve for SAVR and feasibility of treating SVD by V-in-V TAVI.

Custodiol-N™ cardioplegia lowers cerebral inflammation and activation of hypoxia-inducible factor-1α.

OBJECTIVES: Cardioplegic solutions induce cardiac arrest and protect cardiac tissue from ischaemia-reperfusion injury. However, the effects on the brain, which is vulnerable to cardiopulmonary bypass (CPB) surgery and ischaemia-reperfusion injury, mostly remain unknown. We investigated if cardioplegic solutions differ in their effects in altered oxygen conditions and in their ability to induce cerebral inflammation. METHODS: Thirty pigs were subjected to a midline sternotomy and CPB at 34°C with 90 min cardiac arrest followed by 120 min reperfusion. Following randomization on a 1:1:1 basis, they received either a single shot of histidine-tryptophan-α-ketoglutarate (HTK)-Bretschneider solution (n = 10), histidine-tryptophan-α-ketoglutarate-N (HTK-N; n = 10) or HTK plus 1.2 mg/l cyclosporine A (HTK/CsA; n = 10). Brain regions of interest (frontal cortex, cerebellum, brain stem, diencephalon, colliculus superior) were analysed by real time quantitative reverse transcriptase polymerase chain reaction for hypoxia-inducible factor-1α (HIF-1α), tumour necrosis factor-α, interleukin (IL)-10, IL-1ß and IL-1ß receptor as well as by immunohistochemical analysis for HIF-1α. Blood gas and electrolyte analyses were performed. RESULTS: Comparisons between baseline and reperfusion period levels revealed that HTK-N cardioplegia induced a smaller reduction of the haemoglobin content and blood calcium concentrations (hbbaseline: 5.97 ± 0.63 mmol/l; hbreperfusion: 6.16 ± 0.66 mmol/l; P = 0.428; Cabaseline2+: 1.36 ± 0.05 mmol/l; Careperfusion2+: 1.28 ± 0.05 mmol/l; P < 0.001) compared to HTK (hbbaseline: 5.93 ± 0.45 mmol/l; hbreperfusion: 4.72 ± 0.79 mmol/l; P = 0.001; Cabaseline2+: 1.34 ± 0.07 mmol/l; Careperfusion2+: 1.24 ± 0.06 mmol/l; P = 0.004) and HTK/CsA cardioplegia (hbbaseline: 5.88 ± 0.44 mmol/l; hbreperfusion: 5.14 ± 0.87 mmol/l; P = 0.040; Cabaseline2+: 1.38 ± 0.04 mmol/l; Careperfusion2+: 1.20 ± 0.14 mmol/l; P = 0.001). Brain region-specific regulation of the HIF-1α expression, no general HIF-1α activation and a lower tumour necrosis factor-α expression (pto HTK = 0.050, pto HTK/CsA = 0.013) were documented for HTK-N cardioplegia. CONCLUSIONS: HTK-N (Custodiol-N) induced fewer cerebral effects and less inflammation during CPB surgery than HTK and HTK/CsA cardioplegia. These data suggest that HTK-N exerts brain protective effects during and after CPB surgery.

Good 5-Year Durability of Transapical Beating Heart Off-Pump Mitral Valve Repair With Neochordae.

BACKGROUND: Transapical, beating heart, off-pump implantation of neochordae for repair of mitral valve (MV) prolapse is of increasing interest. The aim of this study was to evaluate long term results for MV repair using the NeoChord system (NeoChord, St. Louis Park, MN). METHODS: Six patients underwent treatment for severe primary mitral regurgitation (MR) with the NeoChord DS1000 system as part of the initial device safety and feasibility Transapical Artificial Chordae Tendinae (TACT) trial at our institution (University of Leipzig-Heart Center, Leipzig, Germany). The primary pathology in all patients was isolated posterior leaflet prolapse of the P2 or P3 segment, or both. RESULTS: Successful repair resulting in no or trace MR was achieved in 5 of 6 patients by implantation of three neochordae under transesophageal echocardiographic guidance and normal left ventricular loading conditions. One patient underwent intraoperative conversion to an open MV replacement as a result of leaflet injury. The early postoperative course was uneventful in all remaining patients. Two patients had to undergo reoperation for recurrent MR at 3 and 16 months postoperatively. The remaining 3 patients were followed up for a period of 5 years. These patients were free of cardiac symptoms, and transthoracic examination showed trace or mild to moderate MR at 1-, 2-, and 5-year follow-up. A trend toward reverse remodeling of the left ventricle with no increase in mitral annular dilatation over 5 years was observed. CONCLUSIONS: In select patients, MV repair using the NeoChord system results in very good long-term results without recurrent prolapse, MR, or annular dilatation.

Custodiol versus cold Calafiore for elective cardiac arrest in isolated aortic valve replacement: a propensity-matched analysis of 7263 patients.

OBJECTIVES: This study was designed to assess the impact of crystalloid cardioplegia (CCP) and blood cardioplegia (BCP) on short- and long-term outcome after isolated aortic valve replacement (AVR). METHODS: A total of 7263 patients undergoing AVR at our institution between November 1994 and June 2015 were identified. CCP (Custodiol ® ) was used in 83% ( n = 5998) and intermittent cold BCP in 1007 patients (14%). For 4790 patients, propensity scores were calculated from baseline data, risk factors, comorbidities and characteristics of the disease, resulting in 825 pairs. The primary outcome was operative mortality (OM). RESULTS: There was no significant difference in OM between CCP and BCP cohorts [33 of 825 (4.0%) vs 35 of 825 (4.2%), P = 0.90]. The incidence of postoperative complications was comparable between both groups. Long-term survival was also not different between CCP and BCP (log-rank test: P = 0.9). Multiple Cox regression analysis demonstrated that mortality was significantly affected by renal function ( P < 0.001), logistic EuroSCORE ( P < 0.001), male sex ( P = 0.005) and diabetes ( P = 0.037). Patients with reduced left ventricular ejection fraction ≤30% showed improved survival when receiving BCP intraoperatively [odds ratio: 2.28 (1.12-4.63); P = 0.03]. CONCLUSIONS: CCP and BCP provide equivalent outcome after isolated AVR. However, BCP seems to be beneficial for patients with reduced left ventricular ejection fraction.

Transapical Mitral Valve Implantation for Native Mitral Valve Stenosis Using a Balloon-Expandable Prosthesis.

BACKGROUND: Transcatheter mitral valve implantation (TMVI) is still in its infancy and is mainly limited to valve-in-valve or valve-in-ring implantations. We present the early experience with TMVI for severe calcified native MV stenosis. METHODS: Between January 2014 and June 2015, 6 of 11 patients screened (mean age, 77.4 ± 6.3 years; 66% men) with severe native mitral valve (MV) stenosis (mean gradient [Pmean], 11.1 ± 2.1 mm Hg; mean effective orifice area [EOA], 0.9 ± 0.12 cm2) underwent transcatheter MV replacement at our institution as a bailout procedure. Conventional surgical procedures were denied in all patients because of severe annular calcification and extensive comorbidities (mean logistic EuroScore, 31.4% ± 8.3%). The Edwards SAPIEN 3 (29 mm) (Edwards Lifesciences, Irvine, CA) was used in all cases. Procedural access was transapical in 5 cases and concomitant to aortic valve replacement through the left atrium through a sternotomy in 1 case. RESULTS: Initial implantation was successful in 100% of the cases. Because of early migration, 1 patient needed a valve-in-valve procedure. Postoperative echocardiography showed no residual mitral regurgitation in 4 cases (66%) and mild regurgitation in 2 cases (34%). Mean gradients were reduced to 4.2 ± 0.6 mm Hg (mean EOA, 2.8 ± 0.4 cm2). No patient had a stroke during hospitalization, and 30-day mortality was seen in 1 patient (17%) resulting from pneumonia. CONCLUSIONS: TMV implantation using the SAPIEN 3 aortic prosthesis in patients with heavy annular calcification is feasible and represents a reasonable bailout option for inoperable patients. However, several limitations need to be considered in this special patient population.

Evaluation of conventional and frozen elephant trunk techniques on spinal cord blood flow in an animal model.

OBJECTIVES: The treatment of patients with extensive thoracic aortic disease involving the arch and descending aorta is often performed using the frozen elephant trunk technique (FET). Spinal cord blood flow (SCBF) in cervical, thoracic and lumbar sections prior, during and after aortic arch surgery were compared in conventional elephant trunk (cET) and FET technique in a pig model. METHODS: German Landrace pigs (75-85 kg) underwent aortic arch surgery using the FET (n = 8) or cET (n = 8) techniques. The E-vita Open hybrid stent graft was applied in all FET animals. Regional SCBF was measured 4 times: (i) before cardiopulmonary bypass, (ii) after 1 h, (iii) after 3 h, and (iv) after 6 h of reperfusion using fluorescence microspheres. Spinal cord segments were examined histopathologically and by immunohistochemistry. RESULTS: SCBF in FET decreased significantly from 0.13 ± 0.03 to 0.05 ± 0.02 ml/min/g after 1 h (P = 0.047). While at 3 h of reperfusion, SCBF increased and was comparable to baseline (0.09 ± 0.01 ml/min/g), beyond this time SCBF decreased again (0.05 ± 0.02 ml/min/g). A similar trend was found for SCBF in the cET group (baseline: 0.16 ± 0.04 ml/min/g, 1 h reperfusion: 0.02 ± 0.01 ml/min/g, 3 h reperfusion: 0.03 ± 0.01 ml/min/g and 6 h reperfusion: 0.02 ± 0.01 ml/min/g, P = 0.019). Cervical, thoracic and lumbar SCBF were also comparable in both groups. Histological analyses of spinal cord showed no differences in necrosis between cET and FET, while no differences were found for hypoxia-inducible factor-1α and apoptosis-inducing factor. In contrast, oxidative stress and caspase-induced apoptosis were higher in cET versus FET. CONCLUSIONS: The SCBF changed significantly during extensive aortic arch surgery with circulatory arrest and moderate hypothermia, but such changes were comparable between the FET and cET groups. The implantation of hybrid stent graft did not influence SCBF in thoracic and lumbar segments of the spinal cord. The immunohistological examination showed no differences between cET and FET regarding ischaemic damage and hypoxia-induced effects in spinal cord segments.

Non-invasive spinal cord oxygenation monitoring: validating collateral network near-infrared spectroscopy for thoracoabdominal aortic aneurysm repair.

OBJECTIVES: Near-infrared spectroscopy of the collateral network (cnNIRS) has recently been trialled to monitor real-time tissue oxygenation of the paraspinous vasculature as a surrogate for spinal cord tissue oxygenation. This large animal study was designed to investigate the correlation between cnNIRS and spinal cord oxygenation by comparing it to laser Doppler flowmetry (LDF), a proven method for direct oxygenation and flow assessment. METHODS: Measurements were performed in seven animals. Four paravertebral cnNIRS optodes were positioned bilaterally at thoracic and lumbar levels to assess tissue oxygenation of the paraspinous vasculature. Paravertebral muscle and spinal cord oxygenation and microcirculatory flow were measured directly using LDF probes. LDF and cnNIRS were compared during consecutive repeated periods of descending aortic cross-clamping for 8 min and recovery by clamp release. RESULTS: Following aortic cross-clamping, lumbar cnNIRS signals instantaneously responded with a decrease to 85 ± 4% within 30 s, and to a minimum of 69 ± 6% after 8 min, returning to baseline values after clamp release within 40 s. Direct lumbar muscle and spinal cord oxygenation assessed by LDF responded analogously to cnNIRS (muscle and spinal cord oxygenation after cross-clamping 11.3 ± 6 and 37.6 ± 22% after 5 and 8 min, respectively). Comparison between lumbar cnNIRS and LDF muscle and spinal cord measurements showed a significant positive correlation (r = 0.51-0.52, P < 0.001). Thoracic cnNIRS signals remained relatively stable throughout the procedure. Lumbar paraspinous muscle oxygenation corresponded to direct spinal cord oxygenation (no significant difference, P = 0.296). CONCLUSIONS: These experiments confirm that the paraspinous vasculature in the presented large animal model is directly linked to spinal cord microcirculation and that the regional paraspinous muscle oxygenation status reflects spinal cord tissue oxygenation. As lumbar cnNIRS reproducibly depicts tissue oxygenation of the paraspinous vasculature, it can be used for non-invasive spinal cord oxygenation monitoring in real-time.

Acute type A aortic dissection: characteristics and outcomes comparing patients with bicuspid versus tricuspid aortic valve.

OBJECTIVES: The aim of this study is to investigate the clinical characteristics and postoperative outcome of patients with a bicuspid aortic valve (BAV) suffering acute dissection in comparison with their tricuspid peers. METHODS: Between 1995 and 2011, 460 consecutive patients underwent emergency repair for acute type A aortic dissection. In 379 patients without connective tissue disease, the aortic valve morphology could clearly be specified (91.6% tricuspid and 8.4% bicuspid). RESULTS: At the time of dissection, patients with a bicuspid valve were younger (46.7 ± 13 vs 61.6 ± 12 years, P < 0.001) with the entry tear more often located in the root compared with those with a tricuspid valve (bicuspid: 31.3% vs tricuspid: 6.3%, P < 0.001). Consequently, surgical repair warranted root replacement in 93.8% of bicuspid vs 28.8% of tricuspid valve patients (P < 0.001). The leading pathology was medial necrosis/degeneration in bicuspid and atherosclerosis in tricuspid patients (P = 0.166). Hospital mortality was 20.3% and not significantly different between the two valve morphologies, even despite the younger age of bicuspid patients: 28.1% among bicuspids vs 19.6% among tricuspids (P = 0.255). Survival after discharge was 63.3% at 10 years for all patients. BAV patients had a significantly better survival with 100% at 10 years compared with 60.2% in tricuspid valve patients (P = 0.011). Mean follow-up among survivors was comparable for bicuspid and tricuspid patients (3.7 and 4.1 years, respectively). CONCLUSIONS: Patients with BAV have a distinctive dissection pattern with the entry tear frequently located in the aortic root and-despite their younger age-are subject to substantial hospital mortality. For bicuspid patients suffering from dissection, composite root replacement yields an excellent outcome equal to an age- and gender-matched normal population.

Acute hemodynamic effects of angiotensin- converting enzyme inhibition after prolonged cardiac arrest with Bretschneider's solution.

Evidence as to how ACE inhibitors attenuate ischemia-reperfusion injury (IR) after cardioplegic arrest remains scarce. Twenty-four rabbit hearts were perfused on a Langendorff apparatus. Control hearts (n = 6) were arrested with pure histidine-tryptophan-ketoglutarate (HTK)-Bretschneider. Treatment groups received added to the cardioplegic solution (n = 6) captopril (100 µmol/l) and losartan (100 µmol/l) for selective AT1-receptor antagonism or BQ123 (100 nmol/l) for selective ETA-receptor antagonism. Pre-ischemic equilibration of 45 min was followed by 90 min of cardioplegic arrest and 30 min of reperfusion. Indices of myocardial contractility (LVP, dp/dt max, dp/dt min), coronary flow, heart rate, and O2 consumption were recorded before and after ischemic arrest. Tissue adenosine triphosphate (ATP) and malondialdehyde (MDA) contents were measured to evaluate energy content and oxidative stress, respectively. After selective cardiac arrest with Bretschneider, captopril-treated hearts showed improved hemodynamics compared to control and the other treatment groups. Oxygen consumption was significantly decreased during early reperfusion in captopril-treated hearts (34 ± 3 µmol/min/g/mmHg) compared to controls and losartan- and BQ123-treated hearts (controls: 77 ± 9 µmol/min/g/mmHg, p = 0.003; losartan: 54 ± 9 µmol/min/g/mmHg, p = 0.015; BQ123: 64 ± 13 µmol/min/g/mmHg, p = 0.046). The ATP content of the reperfused tissue was significantly elevated after captopril treatment compared to control group (24 ± 2 vs. 16 ± 2 µmol/g, p = 0.033), whereas the level of MDA was substantially decreased (0.58 ± 0.163 vs. 1.5 ± 0.28 µmol/g, p = 0.009). ACE inhibition leads to a significantly greater and faster recovery of myocardial contractility after prolonged cardiac arrest with Bretschneider solution. Due to decreased oxygen consumption, myocardial protection is enhanced. The association between ACE and ischemia cannot be clarified by selective blockade of angiotensin-II receptor type 1 (AT1-R) or ETa receptor (ETa-R).