Bas A. de Mol

Efficacy of transcranial motor-evoked myogenic potentials to detect spinal cord ischemia during operations for thoracoabdominal aneurysms

OBJECTIVEnMotor-evoked myogenic potentials after transcranial electrical stimulation monitor the vulnerable motoneuronal system of the spinal cord. This study reports our initial experiences with motor-evoked potentials to assess the adequacy of spinal cord perfusion during operations for thoracoabdominal aneurysms.nnnMETHODSnIn 20 patients undergoing thoracoabdominal aneurysm operations, myogenic motor-evoked potentials were recorded. In 18 patients retrograde aortic perfusion was used. When spinal cord ischemia was detected, distal flow or mean arterial pressure was increased in an attempt to restore cord perfusion. By means of sequential crossclamping, motor-evoked potentials were also used to identify intercostal or lumbar arteries that needed to be reimplanted.nnnRESULTSnReproducible motor-evoked potentials could be recorded in all patients. During retrograde perfusion, nine patients showed a rapid decrease in the amplitude of motor-evoked potentials to less than 25% of baseline, indicating spinal cord ischemia. In five patients ischemic changes in motor-evoked potentials could be reversed by increasing distal and proximal blood pressures. In four patients ischemic changes during crossclamping necessitated segmental artery reimplantation. In three of these four patients intercostal or lumbar arteries were reattached. In one patient reimplantation of segmental arteries was not possible; this patient awoke paraplegic. Segmental arteries were ligated after confirmation of intact motor-evoked potentials during aortic clamping in eight patients. None of these patients had a neurologic deficit. The absence of motor-evoked potentials at the end of the procedure always indicated a postoperative motor deficit.nnnCONCLUSIONnDuring operations for thoracoabdominal aneurysms, monitoring of motor-evoked potentials is an effective technique to detect spinal cord ischemia within minutes. This modality can be used to guide the management of distal aortic perfusion techniques and may also help to identify segmental arteries that need to be reattached.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

Generation of platelet-derived microparticles in patients undergoing cardiac surgery is not affected by complement activation

OBJECTIVEnThe mechanisms causing the presence of platelet-derived microparticles in the circulation are unknown. In vitro platelets release platelet-derived microparticles in response to complement activation. This study evaluates the relationship between complement activation and levels of circulating platelet-derived microparticles in patients undergoing cardiac surgery.nnnMETHODSnProspectively, 71 patients were included who underwent elective coronary artery bypass grafting with cardiopulmonary bypass. The patients were randomly allocated to one of the 3 groups: uncoated oxygenator, UnModified Surface (n = 25) or oxygenator coated with either BioPassive Surface (n = 25) or BioActive Surface (n = 21). Platelet-derived microparticles and terminal complement complexes were determined before bypass and after induction of anesthesia, 15 minutes after the start of cardiopulmonary bypass, at the end of cardiopulmonary bypass, and 30 minutes after administration of protamine sulfate.nnnRESULTSnDemographic and cardiopulmonary bypass data were similar for the 3 groups. At the end of cardiopulmonary bypass, platelet-derived microparticle numbers were decreased in all 3 groups. No significant differences were observed among the groups at any sampling point. At the end of cardiopulmonary bypass, terminal complement complex concentrations were increased in all groups (P <.001), and significant differences among the groups were present (P =.002).nnnCONCLUSIONSnDespite significant complement activation, no increase in numbers of circulating platelet-derived microparticles was found in the systemic blood of patients undergoing cardiac surgery with cardiopulmonary bypass. Thus complement activation in vivo does not necessarily affect generation of platelet-derived microparticles.

Clinical outcome after surgical or percutaneous revascularization in coronary bypass graft failure.

Aims To describe long-term outcome following surgical and percutaneous revascularization in graft failure. Methods We analyzed consecutive patients with graft failure after heart-team assignment to percutaneous coronary intervention (PCI) or redo coronary artery bypass grafting (CABG) between 2003 and 2008. The primary endpoint was the composite of death, myocardial infarction (MI) or target vessel revascularization (TVR). Kaplan–Meier event rate estimates were calculated up to a 5-year follow-up. Independent predictors for outcomes were identified by backward selection in a multivariable Cox proportional hazard model. Results We identified 287 patients treated for graft failure: 243 with PCI and 44 with redo CABG. Patients undergoing PCI more frequently presented with ST-elevated myocardial infarction (STEMI) (Pu200a<u200a0.001), multivessel disease (Pu200a<u200a0.001), vein graft failure (Pu200a=u200a0.04), a history of MI (Pu200a<u200a0.001) and shorter time-to-graft failure (Pu200a=u200a0.001). Bare-metal stents (BMS) were used in 81.3% of the PCI-treated lesions and drug-eluting stents (DES) in 18.7%. The median follow-up was 3.9 years. Five-year rate of composite all-cause death, MI or TVR was 57.6% after PCI and 51% after CABG (Pu200a=u200a0.51). Repeat revascularization [TVR and target lesion revascularization (TLR)] was 30.7 and 21.3% after PCI, and 8.0 and 3.2% following CABG (Pu200a=u200a0.009; Pu200a=u200a0.008). In the PCI group, BMS was associated with higher rates of TVR (35.1 vs. 12.6%; Pu200a=u200a0.04) and TLR (24.8 vs. 7.6%; Pu200a=u200a0.04), but similar rate of death or MI compared with DES. Independent predictors for the primary outcome were creatinine [hazard ratio 1.008 per &mgr;mol/l, 95% confidence interval (CI) 1.005–1.011, Pu200a<u200a0.001] and peak creatine kinase MB (hazard ratio 1.001 per U/l, 95% CI 1.000–1.002, Pu200a=u200a0.027). Conclusion Clinical outcomes are similarly poor after heart-team triage for surgical or percutaneous intervention in patients with graft failure. Repeat revascularization occurred more frequent after PCI, particularly following BMS implantation.

Aortic valve calcification as a predictor of location and severity of paravalvular regurgitation after transcatheter aortic valve implantation

OBJECTIVESnTo determine whether the location of aortic valve calcium (AVC) influences the location of paravalvular regurgitation (PR). PR is an adverse effect of transcatheter aortic valve implantation (TAVI) with a negative effect on long-term patient survival. The relationship between AVC and the occurrence of PR has been documented. However, the relationship between the distribution of AVC and the location of PR is still sparsely studied. The purpose of this study was to correlate severity and location of AVC with PR in patients treated with TAVI.nnnMETHODSnFifty-six consecutive patients who underwent transaortic or transapical TAVI and had preoperative computed tomography scans were included in this retrospective study. The volume, mass and location of AVC was determined and compared between patients with and without PR using a non-parametric t-test. Postoperative echocardiography was performed to determine the presence and location of PR, which was associated with the cusp with highest AVC using a χ(2) test.nnnRESULTSnValve deployment was successful in all 56 patients. PR was present in 38 patients (68%) after TAVI. There was a non-significantly higher volume of AVC in the PR group [214 (70-418) vs 371 (254-606) cm(3), P = 0.15]. AVC mass was significantly higher in patients with PR than in patients without PR [282 (188-421) vs 142 (48-259) mg, respectively, P = 0.043]. The location of PR was determined in 36 of these patients. Of these 36 patients, PR occurred at the cusp with the highest AVC in 20 patients (56%, χ(2) P = 0.030).nnnCONCLUSIONSnIn our population, PR was associated with greater AVC mass. Moreover, the location of PR was associated with the cusp with the highest amount of AVC.

Optimization of Suture-Free Laser-Assisted Vessel Repair by Solder-Doped Electrospun Poly(e-caprolactone) Scaffold

Poor welding strength constitutes an obstacle in the clinical employment of laser-assisted vascular repair (LAVR) and anastomosis. We therefore investigated the feasibility of using electrospun poly(ε-caprolactone) (PCL) scaffold as reinforcement material in LAVR of medium-sized vessels. In vitro solder-doped scaffold LAVR (ssLAVR) was performed on porcine carotid arteries or abdominal aortas using a 670-nm diode laser, a solder composed of 50% bovine serum albumin and 0.5% methylene blue, and electrospun PCL scaffolds. The correlation between leaking point pressures (LPPs) and arterial diameter, the extent of thermal damage, structural and mechanical alterations of the scaffold following ssLAVR, and the weak point were investigated. A strong negative correlation existed between LPP and vessel diameter, albeit LPP (484xa0±xa0111xa0mmHg) remained well above pathophysiological pressures. Histological analysis revealed that thermal damage extended into the medial layer with a well-preserved internal elastic lamina and endothelial cells. Laser irradiation of PCL fibers and coagulation of solder material resulted in a strong and stiff scaffold. The weak point of the ssLAVR modality was predominantly characterized by cohesive failure. In conclusion, ssLAVR produced supraphysiological LPPs and limited tissue damage. Despite heat-induced structural/mechanical alterations of the scaffold, PCL is a suitable polymer for weld reinforcement in medium-sized vessel ssLAVR.

Transapical JenaValve in a degenerated Freedom SOLO bioprosthesis.

Degeneration of an aortic bioprosthesis is a complication often requiring high-risk surgical reintervention. Transcatheter aortic valve implantation (TAVI) provides an alternative to high-risk surgery. However, TAVI for a degenerated stentless bioprosthesis becomes more perilous because of the lack of support of a stent and the changed landmarks of the aortic root. Furthermore, the supraannular implantation technique for the stentless Freedom SOLO (Sorin Group, Milan, Italy) bioprosthesis may increase the risk for coronary occlusion after deployment because of the reduced distance between the neoannulus and the coronary ostia. In this setting, the use of the JenaValve (JenaValve Technology, GmbH,M€unchen, Germany) could reduce the risk of coronary ostium obstruction because of the specific design of this device. To illustrate this clinical problem, we present the first reported case after successful transcatheter valve-in-valve implantation of a JenaValve in a degenerated Freedom SOLO.

Aortic Valve Replacement With the Stentless Freedom SOLO Bioprosthesis: A Systematic Review

This systematic review examined the clinical and hemodynamic performance of the stentless Freedom SOLO (Sorin Group, Milan, Italy) aortic bioprosthesis. The occurrence of postoperative thrombocytopenia was also analyzed. The Freedom SOLO is safe to use in everyday practice, with short cross-clamp times, and postoperative pacemaker implantation is notably lower. Valvular gradients are low and remain stable during short-term follow-up. Thrombocytopenia is more severe than in other aortic prostheses; however, this is without clinical consequences. Within a few years, the 15-year follow-up of this bioprosthesis will be known, which will be key to evaluating its long-term durability.

New-onset postoperative atrial fibrillation after aortic valve replacement: Effect on long-term survival

Objective There is a paucity of data on long‐term survival of new‐onset postoperative atrial fibrillation (POAF) after cardiac surgery. Also, mean follow‐up in previous studies is confined to a maximum of one decade. This retrospective, longitudinal cohort study was performed to determine the effect on long‐term survival of new‐onset POAF after aortic valve replacement (AVR) over a mean follow‐up of almost 2 decades. Methods Kaplan‐Meier survival analysis was used to determine long‐term survival after AVR, performed between January 1, 1990, and January 1, 1994, in 569 consecutive patients without a history of atrial fibrillation, divided into 241 patients (42.4%) with and 328 patients (57.6%) without new‐onset POAF. New‐onset POAF was considered in multivariable analysis for decreased long‐term survival. After AVR, patients with new‐onset POAF were treated with the aim to restore sinus rhythm within 24 to 48 hours from onset by medication and when medication failed by direct‐current cardioversion before discharge home. Results Mean follow‐up after AVR was 17.8 ± 1.9 years. Incidence of new‐onset POAF was 42.4%. Kaplan‐Meier overall cumulative survival rates at 15 years of follow‐up were similar in the patients with new‐onset POAF versus those without: 41.5% (95% confidence interval [CI], 35.2‐47.7) versus 41.3% (95% CI, 36.0‐46.7), respectively. New‐onset POAF was not an independent risk factor for decreased long‐term survival (hazard ratio 0.815; 95% CI, 0.663‐1.001; P = .052). Conclusions New‐onset POAF after AVR does not affect long‐term survival when treatment is aimed to restore sinus rhythm before discharge home.

Stentless vs Stented Aortic Valve Bioprostheses in the Small Aortic Root.

In patients with a small aortic root undergoing aortic valve replacement (AVR), the Freedom SOLO bioprosthesis may be the ideal prosthesis because of its stentless design and supra-annular implantation. This study investigated if the stentless Freedom SOLO has an advantage when compared with a stented bioprosthesis in patients with a small aortic root. From April 2005-July 2014, 269 consecutive patients underwent AVR with either a Freedom SOLO (n = 76) or Mitroflow (n = 193) bioprosthesis size 19mm or 21mm, respectively. This retrospective comparison study presents clinical and echocardiographic follow-up data. In results, operative outcome and survival were similar. At 7 years, cumulative incidence of aortic valve reoperation and structural valve deterioration favor the Freedom SOLO (0% vs 7.1%, P = 0.03 and 0% vs 4.5%, P = 0.08, respectively). Additionally, the postoperative peak and mean valvular gradients favor the Freedom SOLO (21 ± 9mmHg vs 32 ± 12mmHg and 12 ± 5mmHg vs 19 ± 8mmHg, both P = <0.001, respectively). During mid-term follow-up this hemodynamic advantage continued in favor of the Freedom SOLO. Also prosthesis-patient mismatch occurred less frequently in the Freedom SOLO (28% vs 52%, P = 0.001). There were no differences in prosthetic valve endocarditis, thromboembolic, or bleeding events. In conclusion, the stentless Freedom SOLO has several significant advantages for AVR in patients with a small aortic root in comparison with a stented Mitroflow bioprosthesis. The Freedom SOLO shows superior hemodynamic performance with significantly lower valvular gradients that remained stable during mid-term follow-up. Additionally, significantly fewer prosthesis-patient mismatch occurred and the Freedom SOLO showed superior durability.