Matthias Bechtel

One-Year Results of Transcatheter Aortic Valve Implantation in Severe Symptomatic Aortic Valve Stenosis

Transcatheter aortic valve implantation (TAVI) is an alternative therapy for symptomatic severe aortic valve stenosis in high-risk patients with several co-morbidities. We evaluated the 1-year effects of TAVI on quality of life, exercise capacity, neurohormonal activation, and myocardial hypertrophy. From June 2008 to October 2009, consecutive patients aged ≥75 years with symptomatic severe aortic valve stenosis (area <1 cm(2)) and a logistic euroSCORE ≥15% or aged >60 years with additional specified risk factors underwent TAVI. An aortic valve prosthesis (CoreValve) was inserted in a retrograde fashion. Examinations were performed before and 30 days and 1 year after TAVI. An assessment of the quality of life (Minnesota Living with Heart Failure Questionnaire), a 6-minute walking test, measurement of B-type natriuretic peptide, and echocardiography were performed. In 51 patients (mean age 78 ± 6.6 years, mean left ventricular ejection fraction 58.4 ± 12.2%), the follow-up examinations were performed after TAVI. The 1-year follow-up visit after TAVI revealed significantly improved quality of life (baseline Minnesota Living with Heart Failure Questionnaire score 39.6 ± 19 vs 26.1 ± 18, p <0.001) and more distance covered in the 6-minute walking test (baseline 185 ± 106 vs 266 ± 118 m, p <0.001). The B-type natriuretic peptide level had decreased (baseline 642 ± 634 vs 323 ± 266 pg/ml, p <0.001), and the left ventricular mass index had decreased (156 ± 45 vs 130 ± 42 g/m(2), p <0.001). The left ventricular diameter and ejection fraction remained unchanged. In conclusion, TAVI leads to significantly reduced neurohormonal activation, regression of myocardial hypertrophy, and lasting enhancement of quality of life and exercise capacity in patients with symptomatic and severe aortic stenosis 1 year after intervention.

Autograft Reinforcement to Preserve Autograft Function After the Ross Procedure A Report From the German-Dutch Ross Registry

Background— Autograft reinforcement interventions (R) during the Ross procedure are intended to preserve autograft function and improve durability. The aim of this study is to evaluate this hypothesis. Methods and Results— 1335 adult patients (mean age:43.5±12.0 years) underwent a Ross procedure (subcoronary, SC, n=637; root replacement, Root, n=698). 592 patients received R of the annulus, sinotubular junction, or both. Regular clinical and echocardiographic follow-up was performed (mean:6.09±3.97, range:0.01 to 19.2 years). Longitudinal assessment of autograft function with time was performed using multilevel modeling techniques. The Root without R (Root−R) group was associated with a 6× increased reoperation rate compared to Root with R (Root+R), SC with R (SC+R), and without R (SC-R; 12.9% versus 2.3% versus 2.5%.versus 2.6%, respectively; P<0.001). SC and Root groups had similar rate of aortic regurgitation (AR) development over time. Root+R patients had no progression of AR, whereas Root−R had 6 times higher AR development compared to Root+R. In SC, R had no remarkable effect on the annual AR progression. The SC technique was associated with lower rates of autograft dilatation at all levels of the aortic root compared to the Root techniques. R did not influence autograft dilatation rates in the Root group. Conclusions— For the time period of the study surgical autograft stabilization techniques preserve autograft function and result in significantly lower reoperation rates. The nonreinforced Root was associated with significant adverse outcome. Therefore, surgical stabilization of the autograft is advisable to preserve long-term autograft function, especially in the Root Ross procedure.

The metabolic and renal effects of adrenaline and milrinone in patients with myocardial dysfunction after coronary artery bypass grafting

IntroductionMyocardial dysfunction necessitating inotropic support is a typical complication after on-pump cardiac surgery. This prospective, randomized pilot study analyzes the metabolic and renal effects of the inotropes adrenaline and milrinone in patients needing inotropic support after coronary artery bypass grafting (CABG).MethodsDuring an 18-month period, 251 patients were screened for low cardiac output upon intensive care unit (ICU) admission after elective, isolated CABG surgery. Patients presenting with a cardiac index (CI) of less than 2.2 liters/minute per square meter upon ICU admission – despite adequate mean arterial (titrated with noradrenaline or sodium nitroprusside) and filling pressures – were randomly assigned to 14-hour treatment with adrenaline (n = 7) or milrinone (n = 11) to achieve a CI of greater than 3.0 liters/minute per square meter. Twenty patients not needing inotropes served as controls. Hemodynamics, plasma lactate, pyruvate, glucose, acid-base status, insulin requirements, the urinary excretion of alpha-1-microglobuline, and creatinine clearance were determined during the treatment period, and cystatin-C levels were determined up to 48 hours after surgery (follow-up period).ResultsAfter two to four hours after ICU admission, the target CI was achieved in both intervention groups and maintained during the observation period. Plasma lactate, pyruvate, the lactate/pyruvate ratio, plasma glucose, and insulin doses were higher (p < 0.05) in the adrenaline-treated patients than during milrinone or control conditions. The urinary excretion of alpha-1-microglobuline was higher in the adrenaline than in the control group 6 to 14 hours after admission (p < 0.05). No between-group differences were observed in creatinine clearance, whereas plasma cystatin-C levels were significantly higher in the adrenaline than in the milrinone or the control group after 48 hours (p < 0.05).ConclusionThis suggests that the use of adrenaline for the treatment of postoperative myocardial dysfunction – in contrast to treatment with the PDE-III inhibitor milrinone – is associated with unwarranted metabolic and renal effects.Clinical trials registration: ClinicalTrials.gov NCT00446017.

Risk factors for acute kidney injury following TA-TAVI or minimally invasive aortic valve replacement: which procedure is less kidney damaging in elderly patients?

BACKGROUND Acute kidney injury (AKI) represents a major complication following aortic valve replacement in elderly patients. The aim of this study was to determine possible risk factors for AKI and to find the ideal strategy, minimally invasive valve replacement (MIS-AVR) or transapical valve implantation (TA-TAVI), regarding the postoperative renal outcome. METHODS A total of 133 patients (age ≥ 75 years, 67 male) with severe aortic stenosis were included over 2 years: 42% were treated with MIS-AVR, 58% underwent TA-TAVI procedure. AKI was considered as a postprocedural 1.5× increase in creatinine or an increase of > 0.3 mg/dL/48 hours. Group differences were tested with chi-square or t-test. AKI risk assumption was analyzed in multiple multivariate logistic regression models. RESULTS EuroSCORE II-related risk assumption was 8.7 ± 6.9 for TA-TAVI and 4.5 ± 5.7 for MIS-AVR (p < 0.001). The overall 30-day survival rate was 93%. Fifty-eight patients developed a risk for AKI and 13 developed a manifest renal injury/failure. Logistic regression analysis revealed a higher AKI risk for TA-TAVI (odds ratio, OR = 2.58; 95% confidence interval, CI = 1.18, 5.63; p = 0.017). EuroSCORE II (OR = 0.98; 95% CI = 0.92, 1.04; p = 0.433); preoperative creatinine (OR = 1.78; 95% CI = 0.67, 4.77; p = 0.249) and estimated glomerular filtration rate (OR = 1.00; 95% CI = 0.97, 1.02; p = 0.655) had no impact on AKI. A regression model adjusting for the variables age, gender, body mass index (BMI), diabetes, and procedure type revealed a higher AKI rate for male gender (OR = 2.41; 95% CI = 1.13, 5.11; p =  0.022). Operation time and radio-contrast media volume had no influence on the AKI-occurrence. There was no correlation between AKI and early mortality. CONCLUSION A higher risk for AKI after TA-TAVI should be considered in the therapy decision, especially in elderly male patients because MIS-AVR still yields excellent results.

State of the art in neuroprotection during acute type A aortic dissection repair

Temporary (TND) or permanent neurologic dysfunctions (PND) represent the main neurological complications following acute aortic dissection repair. The aim of our experimental and clinical research was the improvement and update of the most common neuroprotective strategies which are in present use. Hypothermic circulatory arrest (HCA): Cerebral metabolic suppression at the clinically most used temperatures (18-22°C) is less complete than had been assumed previously. If used as a ‘stand-alone’ neuroprotective strategy, cooling to 15-20°C with a jugular SO2 ≥ 95% is needed to provide sufficient metabolic suppression. Regardless of the depth of cooling, the HCA interval should not exceed 25 min. After 40 min of HCA, the incidence of TND and PND increases, after 60 min, the mortality rate increases. Antegrade selective cerebral perfusion (ASCP): At moderate hypothermia (25-28°C), ASCP should be performed at a pump flow rate of 10ml/kg/min, targeting a cerebral perfusion pressure of 50-60mmHg. Experimental data revealed that these conditions offer an optimal regional blood flow in the cortex (80±27ml/min/100g), the cerebellum (77±32ml/min/100g), the pons (89±5ml/min/100g) and the hippocampus (55±16ml/min/100g) for 25 minutes. If prolonged, does ASCP at 32°C provide the same neuroprotective effect? Cannulation strategy: Direct axillary artery cannulation ensures the advantage of performing both systemic cooling and ASCP through the same cannula, preventing additional manipulation with the attendant embolic risk. An additional cannulation of the left carotid artery ensures a bi-hemispheric perfusion, with a neurologic outcome of only 6% TND and 1% PND. Neuromonitoring: Near-infrared spectroscopy and evoked potentials may prove the effectiveness of the neuroprotective strategy used, especially if the trend goes to less radical cooling. Conclusion: A short interval of HCA (5 min) followed by a more extended period of ASCP (25 min) at moderate hypothermia (28°C), with a pump flow rate of 10ml/kg/min and a cerebral perfusion pressure of 50 mmHg, represents safe conditions for open arch surgery.

Na+/H+exchange inhibitor cariporide: effects on respiratory dysfunction after cardiopulmonary bypass:

The purpose of the present study was to evaluate the potential of the Na+/H+ exchange inhibitor cariporide to protect the lung from injury after cardiopulmonary bypass (CPB). In a randomized placebo-controlled study, 16 pigs were subjected to CPB for 75 min. Administration of vehicle or cariporide (bolus 180 mg, 40 mg/hour) began 30 min pre-CPB and was continued throughout the protocol. The alveolo-arterial O2-gradient (AaDO2), the pulmonary shunt (Qs/Qt), the compliance (Cpl), haemo-dynamic variables and glycerol and water content in lung tissue were measured 10 min before and up to 180 min post-CPB. All animals in the control versus 75% in the cariporide group survived the experiment. At 5 and 60 min post-CPB, the mean AaDO2 and at 5, 60 and 180 min post-CPB, the mean pulmonary vascular resistance index were higher in the cariporide group (p < 0.05), respectively. More lung water accumulation was found in the cariporide group (p < 0.05). Mean Cpl decreased; the Qs/Qt and glycerol in lung tissue increased without significant intergroup difference. In this model, the inhibitor of the Na+/H+ antiporter showed no protective effect on lung injury after CPB and might even have harmful effects on pulmonary vascular tone and function.

Simultaneous Double Valve-in-Valve TAVI Procedure for Failed Bioprostheses

A 78-year-old female patient who had undergone double valve replacement in 2010 presented in 2014 with severe New York Heart Association grade IV dyspnea. The decision was made to perform a transapical valve-in-valve transcatheter aortic valve implantation (TAVI) procedure in the mitral and aortic positions simultaneously. The postoperative course was uneventful, and the patient was extubated 6 hours after the TAVI procedure.

Annular rupture leading to fatal complications in an elderly patient with calcified aortic and mitral annulus undergoing transapical aortic valve implantation.

This case illustrates the awareness that must be taken of the high morphological risk due to the calcifications of both, the aortic and mitral annulus in elderly patients when performing transapical aortic valve implantation. In an 86-year-old, multimorbid woman (logistic EuroSCORE = 27%) with symptomatic aortic stenosis (annular diameter = 23.4 mm) and severe mitral annular calcification, the implantation of a 26-mm Edwards SAPIEN (Edwards Lifesciences, Irvine, California, United States) valve in aortic position was primary successful, with no paravalvular leakage, valve instability, or coronary malperfusion. Second, a persisting transmural bleeding led to hypovolemic shock, which could not be stabilized even after going on cardiopulmonary bypass, and the patient died in the operation room. The autopsy showed a subvalvular ventricular rupture due to a transmural perforation of the calcified fibrotic annulus during valvuloplasty.

Alterations in Titin Properties and Myocardial Fibrosis Correlate With Clinical Phenotypes in Hemodynamic Subgroups of Severe Aortic Stenosis

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Do Not Confuse the Edge-to-Edge Technique With Mitral Valve Stenosis: Methodological Considerations for Echocardiography After Mitral Valve Repair

Severe symptomatic mitral valve dysfunction of different causes may develop over time. When therapeutic intervention is indicated, mitral valve repair should be attempted as the first treatment option. Different techniques are available for reconstructive surgery. Ring implantation, chordae replacement, and quadrangular resection in cases of prolapse are frequently used procedures. The edge-to-edge technique describes the placement of a stay stitch in the central part of the free edge of both leaflets.1 Similarly, a clip can be delivered percutaneously by using the MitraClip system (Abbott Laboratories, Abbott Park, IL) without surgery. Knowledge of this type of valve repair is necessary to evaluate echocardiographic findings correctly after a surgical procedure. Hemodynamic evaluation of the mitral valve comprises measurements of the transvalvular flow velocity and valve orifice area. The orifice area can be assessed by 2dimensional guided planimetry or by using the empiric formula mitral valve area = 220/pressure half-time. This formula has never been evaluated for application in more than one valve orifice. It is unclear whether this method can be used for hemodynamic assessment after valve repair using the edge-to-edge technique. A 65-year-old man underwent reconstructive surgery for symptomatic severe mitral valve regurgitation due to Barlow disease. The surgical procedure and postoperative course were uneventful. Four months after surgery, the patient underwent routine echocardiography. Because of unusual valve morphologic characteristics, a doming-like appearance of the leaflets, and an ambiguous Doppler profile, valve stenosis was suspected. The valve orifice area was calculated as 2.4 cm2 by using the pressure half-time method. The patient was sent for reference echocardiographic evaluation. He was asymptomatic, but a discrete systolic murmur could be detected. Echocardiography showed noncalcified mobile leaflets that were stitched at the leaflet ends (Figure 1A). Two separate orifices were shown in the parasternal short-axis view (Figure 1B). The leaflets were attached in the center, but mobility was not reduced. A transmitral Doppler profile showed a prolonged deceleration with preserved E and A peaks. The mean transvalvular gradient was 4 mm Hg. The orifice area was measured by 2-dimensional guided planimetry with summation of the two single orifice areas and measured 3.2 cm2 (Figure 1B). No valve regurgitation was detected. The above-mentioned echocardiographic findings are characteristic of mitral valve repair using the edge-to-edge technique. With this so-called Alfieri technique, a stay stitch is placed in the central part of the free edge of both leaflets. Using this stitch, symmetry of the halves can be achieved. Repair is completed by suturing the free edge of the medial segments of the anterior and posterior leaflets. The efficacy and durability of this reconstructive technique have been shown previously.1 However, a mitral clip can be delivered by a percutaneous approach, and the echocardiographic features appear to be the same as after a surgical procedure. Knowledge of this type of valve repair is necessary to evaluate echocardiographic findings correctly after these procedures. Morphologic and functional findings should not be