Transatrial, transcatheter mitral VinR implantation is feasible using a minimally invasive off-pump approach. VinR implantation is a promising concept for re-operative surgery for selected patients after failed mitral valve repair.

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Background/Aims: Mitochondrial permeability transition pore (MPTP) opening appears to play a key role in myocardial cell survival after ischemia-reperfusion injury and can be inhibited by cyclosporin A (CsA). We investigated whether low-dose CsA added to histidine-tryptophan-ketoglutarate (HTK) cardioplegia solution could improve myocardial protection during longer periods of global myocardial ischemia as encountered during cardiac surgery. Methods: Rabbit hearts perfused on a Langendorff apparatus were arrested with cold HTK solution containing 1 µmol/l CsA. After 90 min of ischemia, the hearts were reperfused and pmax, max dp/dt, min dp/dt, myocardial stiffness, pO₂, coronary flow and heart rate recorded. Tissue ATP and malondialdehyde (MDA) were measured to assess cell energy content and oxidative stress, respectively. Results: CsA-treated hearts recovered pmax (p = 0.026), max dp/dt (p = 0.028) and min dp/dt (p = 0.025) more quickly and to a greater extent than non-treated hearts. They required markedly less oxygen (p = 0.041) in the first 10 min of reperfusion. Hearts treated with CsA produced 44% less MDA (1.09 vs. 1.93, p = 0.008), while ATP levels were unchanged. Conclusions: HTK cardioplegia solution containing CsA at a dose well below that expected to cause systemic immunosuppressive effects leads to a significant and timelier recovery of myocardial contractility, while consuming less oxygen.

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).

Transatrial, transcatheter mitral VinV implantation is feasible off pump. This is a truly minimally invasive concept to treat patients with failed xenografts using a right lateral minithoracotomy.

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