Porcine myocardial ischemia-reperfusion studies on cardioprotection, ventricular arrhythmia and electrophysiology

Background: Coronary artery disease is the primary cause of death in adults in the industrialised world and ventricular fibrillation associated with myocardial ischemia is the main cause of sudden cardiac death. Restoration of blood flow and preservation of myocardial integrity throughout ischemia and reperfusion is essential to improve clinical outcome. Alteration in calcium handling and its consequences are central features of these events. Sympathico-vagal imbalance and electrophysiological alterations are important predisposing factors for malign ventricular arrhythmia and sudden cardiac death. Aims: To investigate whether ultra-short acting calcium antagonism or spinal cord stimulation (SCS) could reduce myocardial ischemia and infarct size in a porcine closed-chest model. Furthermore, the feasibility of endocardial electromechanical mapping for defining myocardial viability during acute infarction was evaluated. Finally, non-invasive electrophysiological characteristics of ischemia-reperfusion and the occurrence of ventricular arrhythmias were investigated as well as the effects of SCS on these measures and events. Methods: Myocardial infarction was induced by 45 minute coronary occlusion in closed-chest landrace pigs. An ultra-short acting calcium antagonist, clevidipine, was administered into the myocardium at risk. Myocardial viability was assessed by Evans Blue, tetrazolium and endocardial electromechanical mapping and the correlation between these methods was investigated. Three-dimensional vectorcardiography was continuously recorded, analysed offline with regard to depolarisation and repolarisation parameters, and later correlated to myocardial ischemia and ventricular arrhythmia. In a second series of experiments, the effects of SCS were investigated with regards to haemodynamics, infarct size, ventricular arrhythmia and electrophysiology. Results: Clevidipine did not reduce infarct size. Electrical and mechanical activities were both impaired within the infarct zone, but the precision of electromechanical mapping to identify an infarct was poor, and due to intersegmental variability and arrhythmia. All T vector loop parameters changed in response to ischemia. Ventricular arrhythmia was more prevalent during proximal left anterior descending coronary artery occlusion, which was associated with more pronounced electrophysiological alterations. In the SCS group, ventricular arrhythmia occurred less frequently in association with signs of less ischemia and electrical alterations. SCS did not reduce infarct size. Conclusions: Infarct size was neither reduced by ultra-short acting calcium antagonism nor by SCS, but the latter seemed to have cardioprotective properties as it reduced the occurrence of ventricular arrhythmia. Endocardial electromechanical mapping was not feasible for acute myocardial viability assessment

Characteristics and outcomes of patients receiving a second rescue valve during transcatheter aortic valve implantation

Background: Transcatheter aortic valve implantation (TAVI) has become a safe procedure. However, complications occur, including uncommon complications such as valve malposition, which requires the implantation of an additional rescue valve (rescue-AV). The aim was to study the occurrence and outcomes of rescue-AV in a nationwide registry. Methods: The Swedish national TAVI registry was used as the primary data source, where all 6706 TAVI procedures from 2016 to 2021 were retrieved. Nontransfemoral access and planned valve-in-valve were excluded. In total, 79 patients were identified as having had a rescue-AV, and additional detailed data were collected for these patients. This dataset was analyzed for any characteristics that could predispose patients to a rescue-AV. The outcome of patients receiving rescue-AV also was studied. Results: Of the 5948 patients in the study, 1.3% had a rescue-AV. There were few differences between patients receiving 1 valve and rescue-AV patients. For patients receiving a rescue-AV, the 30-day mortality was 15.2% compared to 1.6% in the control group. A poor outcome after rescue-AV was often associated with a second complication; for example, stroke, need for emergency surgery, or heart failure. Among the patients with rescue-AV who survived at least 30 days, landmark analyses showed similar survival rates compared to the control group. Conclusions: Among TAVI patients in a nationwide register, rescue-AV occurred in 1.3% of patients. The 30-day mortality in patients receiving rescue-AV was high, but long-term outcome among 30-day survivors was similar to the control group

Prognostic impact of percutaneous coronary intervention in octogenarians with non-ST elevation myocardial infarction: A report from SWEDEHEART.

To access publisher's full text version of this article click on the hyperlink belowAIMS: Percutaneous coronary intervention (PCI) improves outcomes in non-ST elevation acute coronary syndromes (NSTE-ACSs). Octogenarians, however, were underrepresented in the pivotal trials. This study aimed to assess the effect of PCI in patients ≥80 years old. METHODS AND RESULTS: We used data from the SWEDEHEART registry for all hospital admissions at eight cardiac care centres within Västra Götaland County. Consecutive patients ≥80 years old admitted for NSTE-ACS between January 2000 and December 2011 were included. We performed instrumental variable analysis with propensity score. The primary endpoint was all-cause mortality at 30 days and one year after index hospitalization. During the study period 5200 patients fulfilled the inclusion criteria. In total, 586 (11.2%) patients underwent PCI, the remaining 4613 patients were treated conservatively. Total mortality at 30 days was 19.4% (1007 events) and 39.4% (1876 events) at one year. Thirty-day mortality was 20.7% in conservatively treated patients and 8.5% in the PCI group (adjusted odds ratio 0.34; 95% confidence interval 0.12-0.97, p = 0.044). One-year mortality was 42.1% in the conservatively treated group and 16.3% in the PCI group (adjusted odds ratio 0.97; 95% confidence interval 0.36-2.51, p = 0.847). CONCLUSIONS: PCI in octogenarians with NSTE-ACS was associated with a lower risk of mortality at 30 days. However, this survival benefit was not sustained during the entire study-period of one-year

Hypertension is associated with increased mortality in patients with ischaemic heart disease after revascularization with percutaneous coronary intervention – a report from SCAAR

Background: The prognostic role of hypertension on long-term survival after percutaneous coronary intervention (PCI) is limited and inconsistent. We hypothesize that hypertension increases long-term mortality after PCI. Methods: We analyzed data from SCAAR (Swedish Coronary Angiography and Angioplasty Registry) for all consecutive patients admitted coronary care units in Sweden between January 1995 and May 2013 and who underwent PCI due to ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI)/unstable angina (UA) or stable angina pectoris. We used Cox proportional-hazards regression for statistical modelling on complete-case data as well as on imputed data sets. We used interaction test to evaluate possible effect-modulation of hypertension on risk estimates in several pre-specified subgroups: age categories, gender, diabetes, smoking and indication for PCI (STEMI, NSTEMI/UA and stable angina). Results: During the study period, 175,892 consecutive patients underwent coronary angiography due to STEMI, NSTEMI/UA or stable angina. 78,100 (44%) of these had hypertension. Median follow-up was 5.5 years. After adjustment for differences in patient’s characteristics, hypertension was associated with increased risk for mortality (HR 1.12, 95% CI 1.09–1.15, p < .001). In subgroup analysis, risk was highest in patients less than 65 years, in smokers and in patients with STEMI. The risk was lowest in patients with stable angina (p < .001 for interaction test). Conclusion: Hypertension is associated with higher mortality in patients with STEMI, NSTEMI/UA or stable angina who are treated with PCI