Editor's Choice - Trends in Management and Outcomes of Type B Aortic Dissection: A Report From the International Registry of Aortic Dissection.

OBJECTIVE: To describe the trends in management and outcomes of patients with acute type B aortic dissection in the International Registry of Acute Aortic Dissection. METHODS: From 1996 - 2022, 3 908 patients were divided into similar sized quartiles (T1, T2, T3, and T4). In hospital outcomes were analysed for each quartile. Survival rates following admission were compared using Kaplan-Meier analyses with Mantel-Cox Log rank tests. RESULTS: Endovascular treatment increased from 19.1% in T1 to 37.2% in T4 (ptrend < .001). Correspondingly, medical therapy decreased from 65.7% in T1 to 54.0% in T4 (ptrend < .001), and open surgery from 14.8% in T1 to 7.0% in T4 (ptrend < .001). In hospital mortality decreased in the overall cohort from 10.7% in T1 to 6.1% in T4 (ptrend < .001), as well as in medically, endovascularly and surgically treated patients (ptrend = .017, .033, and .011, respectively). Overall post-admission survival at three years increased (T1: 74.8% vs. T4: 77.3%; p = .006). CONCLUSION: Considerable changes in the management of acute type B aortic dissection were observed over time, with a significant increase in the use of endovascular treatment and a corresponding reduction in open surgery and medical management. These changes were associated with a decreased overall in hospital and three year post-admission mortality rate among quartiles.

Survival after PCI or CABG for left main stem coronary stenosis. A single institution registry from the NOBLE study period.

Objective. To analyze 10 years mortality in an all-comers registry of patients with left main coronary artery stenoses treated with either PCI or CABG. Design. Patients with left main coronary stenoses treated with either PCI or CABG in the period of the NOBLE trial (2010-2015) were all included in an institutional database and registry (University Hospital North Norway). Fifty-six of totally 429 patients were included in the randomized, multicenter and international NOBLE trail; 426 eligible patients from the trial and registry were analyzed for mortality on 20 October 2020. The longest observation time on this date was 3611 days (9.9 years); 205 patients were treated with PCI and 221 with CABG. The patients treated with PCI were 74 ± 10 years vs 68 ± 10 years (CABG). Also, on average the PCI patients had more comorbidities (lower ejection fraction, more peripheral artery disease, more often acute presentation). Results. Survival at the last observation date was 80% for CABG patients vs 48% for PCI. A Cox proportional hazards analysis found PCI to be the strongest independent predictor for mortality (HR = 2.5, 95% CI 1.7-3.7). Also, COPD, chronic kidney disease, age, peripheral vascular disease, cerebrovascular incidents and acute presentation were factor predicting increased 10 years mortality. Conclusion. These data indicate that life expectancy in the overall patient population is shorter for patient treated for left main disease with PCI than with CABG.

The risk factors for radial artery and saphenous vein graft occlusion are different.

Objectives. To determine risk factors for radial artery and saphenous vein graft occlusion during long-term follow-up after coronary artery bypass grafting (CABG). Methods: From a cohort of 119 patients who had received a radial artery graft, 76 - of whom 55 also had at least one saphenous vein graft - underwent a preplanned direct angiography and anthropometric, biochemical, and endothelial function assessment 7.6-12.1 (mean 8.9) years after CABG. Comorbidity, medication, and smoking habits were also recorded. The association between these parameters and conduit longevity was analyzed in univariable and multivariable logistic regression models. Results: Radial artery graft occlusions were associated with higher plasma levels of high-sensitive C-reactive protein and patency was best among patients with pharmacologically treated hypertension. The sole independent risk factor identified for saphenous vein graft occlusion was tobacco smoking 8-12 years postoperatively. Conclusion: Our data support the contention that the pathogenesis of radial artery graft failure is distinct from vein graft disease and is related to hypertension status and systemic inflammation. These risk factors are potential targets for preventive measures. Accordingly, the study supports the eventual design of personalized secondary prevention regimens.Clinical registration number: ISRCTN23118170.

Age-Stratified Outcome in Treatment of Left Main Coronary Artery Stenosis: A NOBLE Trial Substudy.

BACKGROUND: In the treatment of left main coronary artery (LMCA) disease, patients' age may affect the clinical outcome after percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). This study stratified the clinical outcome according to the age of patients treated for LMCA stenosis with PCI or CABG in the Nordic-Baltic-British Left Main Revascularization (NOBLE) study. METHODS: Patients with LMCA disease were enrolled in 36 centers in northern Europe and randomized 1:1 to treatment by PCI or CABG. Eligible patients had stable angina pectoris, unstable angina pectoris, or non-ST elevation myocardial infarction. The primary endpoint was major adverse cardiac or cerebrovascular events (MACCEs), a composite of all-cause mortality, nonprocedural myocardial infarction, any repeat coronary revascularization, and stroke. Age-stratified analysis was performed for the groups younger and older than 67 years and for patients older than 80 years. RESULTS: For patients ≥67 years, the 5-year MACCEs were 35.7 versus 22.3% (hazard ratio [HR] 1.72 [95% confidence interval [CI] 1.27-2.33], p = 0.0004) for PCI versus CABG. The difference in MACCEs was driven by more myocardial infarctions (10.8 vs. 3.8% HR 3.01 [95% CI 1.52-5.96], p = 0.0009) and more repeat revascularizations (19.5 vs. 10.0% HR 2.01 [95% CI 1.29-3.12], p = 0.002). In patients younger than 67 years, MACCE was 20.5 versus 15.3% (HR 1.38 [95% CI 0.93-2.06], p = 0.11 for PCI versus CABG. All-cause mortality was similar after PCI and CABG in both age-groups. On multivariate analysis, age was a predictor of MACCE, along with PCI, diabetes, and SYNTAX score. CONCLUSIONS: As the overall NOBLE results show revascularization of LMCA disease, age of 67 years or older was associated with lower 5-year MACCE after CABG compared to PCI. Clinical outcomes were not significantly different in the subgroup younger than 67 years, although no significant interaction was present between age and treatment. Mortality was similar for all subgroups (ClinicalTrials.gov identifier: NCT01496651).

Direct angiography demonstrates equal 8-12 years patency rates of radial artery and saphenous vein grafts.

Objectives: The benefits of coronary artery bypass surgery depend on lasting graft patency. To aid rational graft selection, the relative long-term merits of radial artery and saphenous vein grafts need to be determined by a gold standard method and with minimal clinically driven selection bias. Methods: The patency rates of various conduits were determined by direct angiography in 76 patients from a cohort of 119 undergoing coronary artery bypass grafting 7.6-12.1 (mean 8.9) years before. Results: 14 out of 76 radial artery and 10 out of 61 saphenous vein grafts were occluded (rates 0.18 and 0.16, respectively). Conclusion: The high long-term patency rate of saphenous vein grafts does not support a preferential use of the radial artery as a coronary artery bypass conduit. Clinical registration number: ISRCTN23118170.

Time of day does not influence outcomes in acute type A aortic dissection: Results from the IRAD.

BACKGROUND: Type A acute aortic dissection (TAAAD) represents a surgical emergency requiring intervention regardless of time of day. Whether such a "evening effect" exists regarding outcomes for TAAAD has not been previously studied using a large registry data. METHODS: Patients with TAAAD were identified from the International Registry of Acute Aortic Dissections (1996-2019). Outcomes were compared between patients undergoing operative repair during the daytime (D), defined as 8 am-5 pm, versus the evening (N), defined as 5 pm-8 am. RESULTS: Four thousand one-hundrd and ninety-seven surgically treated patients with TAAAD were identified, with 1824 patients undergoing daytime surgery (43.5%) and 2373 patients undergoing evening surgery (56.5%). Daytime patients were more likely to have undergone prior cardiac surgery (13.2% vs. 9.5%; p < .001) and have had a prior aortic dissection (4.8% vs. 3.4%; p = .04). Evening patients were more likely to have been transferred from a referring hospital (70.8% vs. 75.0%; p = .003). Daytime patients were more likely to undergo aortic valve sparing root procedures (23.3% vs. 19.2%; p = .035); however, total arch replacement was performed with equal frequency (19.4% vs. 18.8%; p = .751). In-hospital mortality (D: 17.3% vs. N. 16.2%; p = .325) was similar between both groups. Subgroup analysis examining the effect of weekend presentation revealed no significant mortality difference. CONCLUSIONS: A majority of TAAAD patients underwent surgical repair at night. There were higher rates of postoperative tamponade in evening patients; however, mortality was similar. The expertise of cardiac-dedicated operative and critical care teams regardless of time of day as well as training paradigms may explain similar mortality outcomes in this high risk population.

Insights From the International Registry of Acute Aortic Dissection: A 20-Year Experience of Collaborative Clinical Research.

Acute aortic dissection (AAD) is a life-threatening condition associated with high morbidity and mortality rates, and it remains a challenge to diagnose and treat. The International Registry of Acute Aortic Dissection was established in 1996 with the mission to raise awareness of this condition and provide insights to guide diagnosis and treatment. Since then, >7300 cases have been included from >51 sites in 12 countries. Although presenting symptoms and physical findings have not changed significantly over this period, the use of computed tomography in the diagnosis has increased, and more patients are managed with interventional procedures: surgery in type A AAD and endovascular therapy in type B AAD; with these changes in care, there has been a significant decrease in overall in-hospital mortality in type A AAD but not in type B AAD. Herein, we summarized the key lessons learned from this international registry of patients with AAD over the past 20 years.

Propulsion of blood through the right heart circulatory system.

Venous return, the right heart function and the pulmonary circulation is an integrated functional unit. The right ventricle is particularly load sensitive, and will be influenced directly by the venous and pulmonary physiology. In this paper we present important physiological principles that govern the diagnosis and treatment of dysfunctions affecting the return of blood to the heart and the transfer of the cardiac output from the right to the left side. We do evaluate both basic science and the clinical literature pointing to practical aspects of physiological knowledge.

The International Registry of Acute Aortic Dissections (IRAD) - experiences from the first 20 years.

An international collaboration on various aspects of acute aortic syndromes, IRAD or The International Registry of Acute Aortic Dissections, is celebrating its 20th anniversary this year (2016). In this paper, we present important lessons learned during these first 20 years.

Changes in Right Ventricular Shape and Deformation Following Coronary Artery Bypass Surgery-Insights from Echocardiography with Strain Rate and Magnetic Resonance Imaging.

BACKGROUND: This study was designed to assess whether altered RV geometry and deformation parameters persisted well into the recovery period after presumably uncomplicated coronary artery bypass grafting (CABG). It was our hypothesis that the altered geometry of and load in the RV following pericardial opening would change both regional and global deformation indices for an extensive period postoperatively. METHODS AND RESULTS: Fifty-seven patients scheduled for CABG underwent preoperative and 8-10 months postoperative magnetic resonance imaging (MRI) for RV volume measurements, and resting echocardiography with assessment of geometry and RV mechanical function determined by tissue Doppler imaging (TDI) based longitudinal strain. Both MRI and echocardiography revealed postoperative dilatation of the RV apex, shortened longitudinal RV length but unchanged RV ejection fraction. Echocardiography parameters associated with filling of the right atrium showed signs of constraint with a reduced systolic filling fraction and increased right atrial size. Right ventricular segmental strain (-20 ± 13% vs. -29 ± 20% preoperatively; mean ±SD, P < 0.0001) was reduced postoperatively in parallel with TAPSE (1.3 ± 0.3 cm vs. 2.2 ± 0.4 cm; P < 0.0001). CONCLUSION: Post-CABG longitudinal motion of the RV lateral wall is reduced after uneventful CABG despite preserved RV ejection fraction and stroke volume. The discrepancy in various RV systolic performance indicators results from increased sphericity of the RV following opening the pericardium during surgery. Therefore, longitudinal functional parameters may underestimate RV systolic function for at least 8-10 months post-CABG. Changes in deformation parameters should thus always be interpreted in relation to changes in geometry.

Outcomes of patients presenting with acute type A aortic dissection in the setting of prior cardiac surgery: an analysis from the International Registry of Acute Aortic Dissection.

BACKGROUND: Prior cardiac surgery (PCS) can complicate the presentation and management of patients with type A acute aortic dissection (TAAAD). This report from the International Registry of Acute Aortic Dissection examines this hypothesis. METHODS AND RESULTS: A total of 352 of 2196 patients with TAAAD (16%) enrolled in the International Registry of Acute Aortic Dissection had cardiac surgery before dissection, including coronary artery bypass grafting (34%), aortic or mitral valve surgery (36%), aortic surgery (42%), and other cardiac surgery (16%). Those with PCS were older, had a higher frequency of diabetes mellitus, hypertension, and atherosclerosis, and presented later from symptom onset to hospital presentation and diagnosis (all P<0.05). In-hospital mortality was significantly higher for PCS patients (34% versus 23%; P<0.001). Five-year mortality was independently predicted by PCS (hazard ratio [HR], 2.04; 95% confidence interval [CI], 1.05-3.95), age >70 years (HR, 2.65; 95% CI, 1.40-5.05), medical management (HR, 5.10; 95% CI, 2.43-10.71), distal communication (HR, 2.64; 95% CI, 1.35-5.14), and coma (HR, 9.50; 95% CI, 2.05-44.05). Among patients with PCS, in-hospital (43% medical versus 30% surgical; P=0.033) and intermediate-term mortality was higher in patients with medical versus surgical management. Propensity-matched analysis revealed significant increase in mortality with medical management, but not with PCS. CONCLUSIONS: PCS delays presentation, diagnosis, and treatment of TAAAD and is an important adverse risk factor for early and intermediate-term mortality. This effect may be because of increased medical management in this patient population.

Axillary vs Femoral Arterial Cannulation in Acute Type A Dissection: International Multicenter Data.

BACKGROUND: Cannulation strategy in acute type A dissection (ATAD) varies widely without known gold standards. This study compared ATAD outcomes of axillary vs femoral artery cannulation in a large cohort from the International Registry of Acute Aortic Dissection (IRAD). METHODS: The study retrospectively reviewed 2145 patients from the IRAD Interventional Cohort (1996-2021) who underwent ATAD repair with axillary or femoral cannulation (axillary group: n = 1106 [52%]; femoral group: n = 1039 [48%]). End points included the following: early mortality; neurologic, respiratory, and renal complications; malperfusion; and tamponade. All outcomes are presented as axillary with respect to femoral. RESULTS: The proportion of patients younger than 70 years in both groups was similar (n = 1577 [74%]), as were bicuspid aortic valve, Marfan syndrome, and previous dissection. Patients with femoral cannulation had slightly more aortic insufficiency (408 [55%] vs 429 [60%]; P = .058) and coronary involvement (48 [8%] vs 70 [13%]; P = .022]. Patients with axillary cannulation underwent more total aortic arch (156 [15%] vs 106 [11%]; P = .02) and valve-sparing root replacements (220 [22%] vs 112 [12%]; P < .001). More patients with femoral cannulation underwent commissural resuspension (269 [30.9%] vs 324 [35.3%]; P = .05). Valve replacement rates were not different. The mean duration of cardiopulmonary bypass was longer in the femoral group (190 [149-237] minutes vs 196 [159-247] minutes; P = .037). In-hospital mortality was similar between the axillary (n = 165 [15%]) and femoral (n = 149 [14%]) groups (P = .7). Furthermore, there were no differences in stroke, visceral ischemia, tamponade, respiratory insufficiency, coma, or spinal cord ischemia. CONCLUSIONS: Axillary cannulation is associated with a more stable ATAD presentation, but it is a more extensive intervention compared with femoral cannulation. Both procedures have equivalent early mortality, stroke, tamponade, and malperfusion outcomes after statistical adjustment.

Neurological event rates and associated risk factors in acute type B aortic dissections treated by thoracic aortic endovascular repair.

OBJECTIVES: Thoracic endovascular aortic repair is the method of choice in patients with complicated type B acute aortic dissection. However, thoracic endovascular aortic repair carries a risk of periprocedural neurological events including stroke and spinal cord ischemia. We aimed to look at procedure-related neurological complications within a large cohort of patients with type B acute aortic dissection treated by thoracic endovascular aortic repair. METHODS: Between 1996 and 2021, the International Registry of Acute Aortic Dissection collected data on 3783 patients with type B acute aortic dissection. For this analysis, 648 patients with type B acute aortic dissection treated by thoracic endovascular aortic repair were included (69.4% male, mean age 62.7 ± 13.4 years). Patients were excluded who presented with a preexisting neurologic deficit or received adjunctive procedures. Demographics, clinical symptoms, and outcomes were analyzed. The primary end point was the periprocedural incidence of neurological events (defined as stroke, spinal cord ischemia, transient neurological deficit, or coma). Predictors for perioperative neurological events and follow-up outcomes were considered as secondary end points. RESULTS: Periprocedure neurological events were noted in 72 patients (11.1%) and included strokes (n = 29, 4.6%), spinal cord ischemias (n = 21, 3.3%), transient neurological deficits (n = 16, 2.6%), or coma (n = 6, 1.0%). The group with neurological events had a significantly higher in-hospital mortality (20.8% vs 4.3%, P < .001). Patients with neurological events were more likely to be female (40.3% vs 29.3%, P = .077), and aortic rupture was more often cited as an indication for thoracic endovascular aortic repair (38.8% vs 16.5%, P < .001). In patients with neurological events, more stent grafts were used (2 vs 1 stent graft, P = .002). Multivariable logistic regression analysis showed that aortic rupture (odds ratio, 3.12, 95% confidence interval, 1.44-6.78, P = .004) and female sex (odds ratio, 1.984, 95% confidence interval, 1.031-3.817, P = .040) were significantly associated with perioperative neurological events. CONCLUSIONS: In this highly selected group from dedicated aortic centers, more than 1 in 10 patients with type B acute aortic dissection treated by thoracic endovascular aortic repair had neurological events, in particular women. Further research is needed to identify the causes and presentation of these events after thoracic endovascular aortic repair, especially among women.

Acute aortic intramural hematoma: an analysis from the International Registry of Acute Aortic Dissection.

BACKGROUND: Acute aortic intramural hematoma (IMH) is an important subgroup of aortic dissection, and controversy surrounds appropriate management. METHODS AND RESULTS: Patients with acute aortic syndromes in the International Registry of Acute Aortic Dissection (1996-2011) were evaluated to examine differences between patients (based on the initial imaging test) with IMH or classic dissection (AD). Of 2830 patients, 178 had IMH (64 type A [42%], 90 type B [58%], and 24 arch). Patients with IMH were older and presented with similar symptoms, such as severe pain. Patients with type A IMH were less likely to present with aortic regurgitation or pulse deficits and were more likely to have periaortic hematoma and pericardial effusion. Although type A IMH and AD were managed medically infrequently, type B IMH were more frequently treated medically. Overall in-hospital mortality was not statistically different for type A IMH compared to AD (26.6% versus 26.5%; P=0.998); type A IMH managed medically had significant mortality (40.0%), although less than classic AD (61.8%; P=0.195). Patients with type B IMH had a hospital mortality that was less but did not differ significantly (4.4% versus 11.1%; P=0.062) from classic AD. One-year mortality was not significantly different between AD and IMH. CONCLUSIONS: Acute IMH has similar presentation to classic AD but is more frequently complicated with pericardial effusions and periaortic hematoma. Patients with IMH have a mortality that does not differ statistically from those with classic AD. A small subgroup of type A IMH patients are managed medically and have a significant in-hospital mortality.

High-resolution visualization and assessment of basal and OXPHOS-induced mitophagy in H9c2 cardiomyoblasts.

Mitochondria are susceptible to damage resulting from their activity as energy providers. Damaged mitochondria can cause harm to the cell and thus mitochondria are subjected to elaborate quality-control mechanisms including elimination via lysosomal degradation in a process termed mitophagy. Basal mitophagy is a house-keeping mechanism fine-tuning the number of mitochondria according to the metabolic state of the cell. However, the molecular mechanisms underlying basal mitophagy remain largely elusive. In this study, we visualized and assessed the level of mitophagy in H9c2 cardiomyoblasts at basal conditions and after OXPHOS induction by galactose adaptation. We used cells with a stable expression of a pH-sensitive fluorescent mitochondrial reporter and applied state-of-the-art imaging techniques and image analysis. Our data showed a significant increase in acidic mitochondria after galactose adaptation. Using a machine-learning approach we also demonstrated increased mitochondrial fragmentation by OXPHOS induction. Furthermore, super-resolution microscopy of live cells enabled capturing of mitochondrial fragments within lysosomes as well as dynamic transfer of mitochondrial contents to lysosomes. Applying correlative light and electron microscopy we revealed the ultrastructure of the acidic mitochondria confirming their proximity to the mitochondrial network, ER and lysosomes. Finally, exploiting siRNA knockdown strategy combined with flux perturbation with lysosomal inhibitors, we demonstrated the importance of both canonical as well as non-canonical autophagy mediators in lysosomal degradation of mitochondria after OXPHOS induction. Taken together, our high-resolution imaging approaches applied on H9c2 cells provide novel insights on mitophagy during physiologically relevant conditions. The implication of redundant underlying mechanisms highlights the fundamental importance of mitophagy.Abbreviations: ATG: autophagy related; ATG7: autophagy related 7; ATP: adenosine triphosphate; BafA1: bafilomycin A1; CLEM: correlative light and electron microscopy; EGFP: enhanced green fluorescent protein; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; OXPHOS: oxidative phosphorylation; PepA: pepstatin A; PLA: proximity ligation assay; PRKN: parkin RBR E3 ubiquitin protein ligase; RAB5A: RAB5A, member RAS oncogene family; RAB7A: RAB7A, member RAS oncogene family; RAB9A: RAB9A, member RAS oncogene family; ROS: reactive oxygen species; SIM: structured illumination microscopy; siRNA: short interfering RNA; SYNJ2BP: synaptojanin 2 binding protein; TEM: transmission electron microscopy; TOMM20: translocase of outer mitochondrial membrane 20; ULK1: unc-51 like kinase 1.

Venoarterial extracorporeal membrane oxygenation or standard care in patients with cardiogenic shock complicating acute myocardial infarction: the multicentre, randomised EURO SHOCK trial.

BACKGROUND: Cardiogenic shock (CGS) occurs in 10% of patients presenting with acute myocardial infarction (MI), with in-hospital mortality rates of 40-50% despite revascularisation. AIMS: The EURO SHOCK trial aimed to determine if early use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) could improve outcomes in patients with persistent CGS following primary percutaneous coronary intervention (PPCI). METHODS: This multicentre, pan-European trial randomised patients with persistent CGS 30 minutes after PPCI of the culprit lesion to receive either VA-ECMO or continue with standard therapy. The primary outcome measure was 30-day all-cause mortality in an intention-to-treat analysis. Secondary endpoints included 12-month all-cause mortality and 12-month composite of all-cause mortality or rehospitalisation due to heart failure. RESULTS: Due to the impact of the COVID-19 pandemic, the trial was stopped before completion of recruitment, after randomisation of 35 patients (standard therapy n=18, VA-ECMO n=17). Thirty-day all-cause mortality occurred in 43.8% of patients randomised to VA-ECMO and in 61.1% of patients randomised to standard therapy (hazard ratio [HR] 0.56, 95% confidence interval [CI]: 0.21-1.45; p=0.22). One-year all-cause mortality was 51.8% in the VA-ECMO group and 81.5% in the standard therapy arm (HR 0.52, 95% CI: 0.21-1.26; p=0.14). Vascular and bleeding complications occurred more often in the VA-ECMO arm (21.4% vs 0% and 35.7% vs 5.6%, respectively). CONCLUSIONS: Due to the limited number of patients recruited to the trial, no definite conclusions could be drawn from the available data. Our study demonstrates the feasibility of randomising patients with CGS complicating acute MI but also illustrates the challenges. We hope these data will inspire and inform the design of future large-scale trials.

Adrenomedullin-epinephrine cotreatment enhances cardiac output and left ventricular function by energetically neutral mechanisms.

Adrenomedullin (AM) used therapeutically reduces mortality in the acute phase of experimental myocardial infarction. However, AM is potentially deleterious in acute heart failure as it is vasodilative and inotropically neutral. AM and epinephrine (EPI) are cosecreted from chromaffin cells, indicating a physiological interaction. We assessed the hemodynamic and energetic profile of AM-EPI cotreatment, exploring whether drug interaction improves cardiac function. Left ventricular (LV) mechanoenergetics were evaluated in 14 open-chest pigs using pressure-volume analysis and the pressure-volume area-myocardial O(2) consumption (PVA-MVo(2)) framework. AM (15 ng·kg(-1)·min(-1), n = 8) or saline (controls, n = 6) was infused for 120 min. Subsequently, a concurrent infusion of EPI (50 ng·kg(-1)·min(-1)) was added in both groups (AM-EPI vs. EPI). AM increased cardiac output (CO) and coronary blood flow by 20 ± 10% and 39 ± 14% (means ± SD, P < 0.05 vs. baseline), whereas controls were unaffected. AM-EPI increased CO and coronary blood flow by 55 ± 17% and 75 ± 16% (P < 0.05, AM-EPI interaction) compared with 13 ± 12% (P < 0.05 vs. baseline) and 18 ± 31% (P = not significant) with EPI. LV systolic capacitance decreased by -37 ± 22% and peak positive derivative of LV pressure (dP/dt(max)) increased by 32 ± 7% with AM-EPI (P < 0.05, AM-EPI interaction), whereas no significant effects were observed with EPI. Mean arterial pressure was maintained by AM-EPI and tended to decrease with EPI (+2 ± 13% vs. -11 ± 10%, P = not significant). PVA-MVo(2) relationships were unaffected by all treatments. In conclusion, AM-EPI cotreatment has an inodilator profile with CO and LV function augmented beyond individual drug effects and is not associated with relative increases in energetic cost. This can possibly take the inodilator treatment strategy beyond hemodynamic goals and exploit the cardioprotective effects of AM in acute heart failure.

Reassessment of a suggested pharmacological approach to heart failure: L-arginine is only a marginal NO donor in pigs.

OBJECTIVES: L-Arginine has been tested in various cardiovascular diseases, mainly to improve endothelial function through NO production. However, as the results have been partly unpredictable, we assessed the hemodynamic, energetic and metabolic effects of L-arginine to clarify any potential benefits in postischemic left ventricular (LV) dysfunction. METHODS: LV dysfunction was induced by repetitive brief coronary occlusions in 12 anesthetized, open chest pigs. L-Arginine was subsequently infused (bolus 400 mg·kg and continuously for 1 hour, 250 mg·kg·h). Hemodynamic parameters, metabolites of L-arginine and myocardial energetics were assessed sequentially. RESULTS: L-Arginine infusions caused a substantial rise in plasma L-arginine (3474 ± 358 µmole·L) accompanied by a 2-fold increase in plasma L-citrulline. No significant alterations in vascular resistance or LV contractility were observed from L-arginine. Mean arterial pressure dropped from 78 ± 11 to 72 ± 10 mm Hg (P = 0.019) and 70 ± 8 mm Hg (P = 0.003) after bolus and infusions, respectively. Myocardial oxygen consumption was unaltered, and myocardial creatine content was not increased after 90 minutes of L-arginine infusion. CONCLUSION: L-Arginine infusion did not influence the energetic cost of myocardial contractility, and only minor hemodynamic changes were observed despite a demonstrable turnover of L-arginine. These findings question the use of L-arginine to promote therapeutic NO formation in the acute setting.

Clinically induced hypothermia with cardiopulmonary support in a high-risk patient undergoing carotid endarterectomy.

Contralateral carotid occlusion increases the risk of stroke by hypoperfusion in patients undergoing carotid surgery. We present the case of a high-risk patient with crescendo cerebral ischemic events, for whom clinically induced hypothermia controlled by cardiopulmonary bypass was applied as a protective measure during carotid endarterectomy.

Mitochondrial dynamics and quantification of mitochondria-derived vesicles in cardiomyoblasts using structured illumination microscopy.

Mitochondria are essential energy-providing organelles of particular importance in energy-demanding tissue such as the heart. The production of mitochondria-derived vesicles (MDVs) is a cellular mechanism by which cells ensure a healthy pool of mitochondria. These vesicles are small and fast-moving objects not easily captured by imaging. In this work, we have tested the ability of the optical super-resolution technique 3DSIM to capture high-resolution images of MDVs. We optimized the imaging conditions both for high-speed video microscopy and fixed-cell imaging and analysis. From the 3DSIM videos, we observed an abundance of MDVs and many dynamic mitochondrial tubules. The density of MDVs in cells was compared for cells under normal growth conditions and cells during metabolic perturbation. Our results indicate a higher abundance of MDVs in H9c2 cells during glucose deprivation compared with cells under normal growth conditions. Furthermore, the results reveal a large untapped potential of 3DSIM in MDV research.