Early outcomes of thoracoscopic trans-mitral myectomy in obstructive hypertrophic cardiomyopathy patients with left midventricular obstruction / 中华外科杂志

Objective: To examine the early effect of thoracoscopic trans-mitral myectomy for hypertrophic cardiomyopathy patients with left midventricular obstruction. Methods: From April 2020 to July 2021, 10 hypertrophic cardiomyopathy patients with left midventricular obstruction underwent thoracoscopic trans-mitral myectomy at Guangdong Provincial People's Hospital. The whole group of patients consisted of 7 males and 3 females aged (52.0±16.4) years (range: 18 to 68 years). The EuroSCORE Ⅱ predicted mortality rate was 1.78% (1.20%) (M(IQR)) (range: 0.96% to 4.86%). The clinical data were collected and analyzed retrospectively to evaluate the clinical efficacy by comparing preoperative and postoperative echocardiographic parameters using paired t-test, paired Wilcoxon test or Fisher exact test, including left ventricular outflow tract peak pressure gradient, maximum interventricular septum thickness, systolic anterior motion of the anterior mitral leaflet and so on. The safety was determined by summarizing the incidence of perioperative and follow-up complications. Results: All the procedures successed with no conversion to median sternotomy, septal defect, ventricular rupture. There was no in-hospital 30-day death, neither serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndrome. The left ventricular outflow tract obstruction was effectively relieved in all patients expect a patient developed residual obstruction. Compared with that of pre-operation, the thickness of the interventricular septum was significantly reduced from (22.1±4.0) mm to (10.3±1.7) mm (t=10.693, P<0.01), while the left ventricular outflow tract peak pressure gradient was significantly reduced from (81.7±21.1) mmHg to 12.3 (11.5) mmHg (Z=-2.805, P<0.01) (1 mmHg=0.133 kPa). Conclusion: Thoracoscopic trans-mitral myectomy is an effective and safe procedure for hypertrophic cardiomyopathy patients with left midventricular obstruction.

Current status and thought of transcatheter mitral edge-to-edge repair in the treatment of hypertrophy cardiomyopathy / 中华外科杂志

Septal reduction therapies, which include septal myectomy and alcohol septal ablation and so on, are the current treatment strategies for patients with obstructive hypertrophic cardiomyopathy and drug-refractory symptoms. With the deepening of theoretical understanding and the rapid development of interventional therapies, some researchers have tried to perform transcatheter mitral valve edge-to-edge repair to treat high-risk patients with hypertrophic cardiomyopathy, including obstructive and non-obstructive. The reported results are relatively satisfactory, but many urgent problems need to be solved, such as the lack of data on animal experiments and large cohort studies, and the unknown medium- and long-term outcomes. However, transcatheter mitral valve edge-to-edge repair brings new ideas for the diagnosis and treatment of patients with hypertrophic cardiomyopathy. On one hand, it can be used as a monotherapy, on the other hand, it can be combined with novel molecular targeted drug therapy or emerging minimally invasive surgical procedures targeting hypertrophic ventricular septum, which deserves our further attention and exploratory research.

Surgery for obstructive hypertrophic cardiomyopathy: challenge and future / 中华外科杂志

After more than 60 years of development, with the deepening of the pathophysiological understanding of obstructive hypertrophic cardiomyopathy, the extent and resection thickness of myectomy have increased significantly. Myectomy combined with the correction of anomalies of the mitral valve apparatus has become the standard treatment of obstructive hypertrophic cardiomyopathy. Only a few centers worldwide can routinely perform it due to the difficulty. Because of the advances of new drugs and interventional therapy, the development of surgical treatment faces many challenges. At the same time, generations of cardiovascular surgeons are constantly trying to promote septal myectomy, including developing devices and the surgical field, as well as improving surgical planning by advanced technology. At present, the superior long-term efficacy of septal myectomy has been confirmed. It is necessary to work together to promote the treatment of hypertrophic obstructive cardiomyopathy, so as to guard people's health.

Effect analysis of myectomy guided by personalized three-dimensional reconstruction and printing in the treatment of obstructive hypertrophic cardiomyopathy / 中华外科杂志

Objective: To examine the clinical efficacy of myectomy guided by personalized three-dimensional reconstruction and printing for patients with obstructive hypertrophic cardiomyopathy. Methods: The clinical data of 28 patients with obstructive hypertrophic cardiomyopathy, who underwent septal myectomy guided by personalized three-dimensional reconstruction and printing in the Department of Cardiaovascular Surgery, Guangdong Provincial People's Hospital from May 2020 to December 2021, were retrospectively analyzed. There were 14 males and 14 females, aging (51.1±14.0) years (range: 18 to 72 years). Enhanced cardiac computed tomography images were imported into Mimics software for preoperative three-dimensional reconstruction. The direction of the short axial plane of each segment was marked perpendicularly to the interventricular septum on the long axial plane of the digital cardiac model, then the thickness was measured on each short axial plane. A figurative digital model was used to determine the extent of resection and to visualize mitral valve and papillary muscle abnormalities. Correlation between the length, width, thickness, and volume of the predicted resected myocardium and those of the surgically resected myocardium was assessed by Pearson correlation analysis or Spearman correlation analysis. The accuracy of detecting mitral valve and papillary muscle abnormalities of transthoracic echocardiography and three-dimensional reconstruction was also compared. Results: There was no death or serious complications like permanent pacemaker implantation, re-sternotomy for bleeding, low cardiac output syndrome, stroke, or multiple organ dysfunction syndromes in the whole group. Namely, the obstruction of the left ventricular outflow tract was effectively relieved. The systolic anterior motion of the anterior mitral valve leaflet was absent in all patients after myectomy. The length, width, and thickness of the predicted resected myocardium by three-dimensional reconstruction were significantly positively correlated with the length (R=0.65, 95%CI: 0.37 to 0.82, P<0.01), width (R=0.39, 95%CI: 0.02 to 0.67, P<0.01), and thickness (R=0.82, 95%CI: 0.65 to 0.92, P<0.01) of the surgically resected myocardium, while the relation of the volume of the predicted resected myocardium and the volume of the surgically resected myocardium was a strong positive correlation (R=0.88, 95%CI: 0.76 to 0.94, P<0.01). Importantly, the interventricular septal myocardial thickness measured by preoperative transthoracic echocardiography showed a moderate positive correlation with the volume of surgically resected myocardium (R=0.52, 95%CI: 0.19 to 0.75, P<0.01). During a follow-up of (14.4±6.8) months (range: 3 to 22 months), no death occurred, and 1 patient was readmitted for endocardial radiofrequency ablation due to atrial fibrillation. Conclusion: Personalized three-dimensional reconstruction and printing can not only visualize the intracardiac structure but also guide septal myectomy by predicting the thickness, volume, and extent of resected myocardium to achieve ideal resection.

Effects of Ringer's solution with different concentrations of alcohol on biphasic compound action potentials of frog sciatic nerve trunk / 中国应用生理学杂志

OBJECTIVE@#To quantitatively investigate the effects of Ringer's solution with different concentrations of alcohol (1%～80%) on biphasic compound action potentials (AP) from frog sciatic nerve trunk, and their recoveries from alcohol effects.@*METHODS@#Individual segments of frog sciatic nerve trunk with a length of 6 to 8 cm were prepared. Ringer's solution with different concentrations of alcohol (0%, 1%, 2%, 4%, 8%, 16%, 32%, 48%, 64% and 80%) was applied onto the segment of the trunk between the stimulus and ground electrodes via an agent reservoir which was newly armed in a nerve trunk shielded chamber for 5 minutes. The nerve trunk was respectively electro-stimulated to generate the biphasic compound AP which was recorded using the experimental system of BL-420F. This was followed by 5 times washout plus 5 min administration with Ringer's solution before recovery recording of AP.@*RESULTS@#Compared to normal Ringer's solution, Ringer's solution with alcohol at ≤4% did not have dramatic impacts on the AP amplitude and conduction velocity, while Ringer's solution with alcohol at ≥8% there was significant decrease in these two parameters. Ringer's solution with alcohol at the conentrations of 16%, 32% and ≥48% could prevent a small proportion (30%), a large proportion (90%) and all (100%) of sciatic nerve trunks, respectively, from generating AP. Washout with normal Ringer's solution after alcohol application at the concentration of ≤32%, AP could totally recover to normal status. While alcohol at the concentration of 48%, 64% and 80%, the probabilities to regenerate APs were 90%, 40% and 0%, and the AP amplitudes were decreased to 60%, 36% and 0%, respectively. After washout, AP conduction velocity showed no difference with alcohol at the concentration of ≤8% when compared with that before washout, while it could not be recovered to normal under alcohol at ≥16%.@*CONCLUSION@#Ringer's solution with different concentrations of alcohol exerts different effects on biphasic compound AP amplitude and conduction velocity. Hopefully, our findings could be helpful for the alcoholic usage and its recovery from alcoholic damage.