Transapical intramyocardial septal microwave ablation in treatment of hypertrophic obstructive cardiomyopathy: 12-month outcomes of a swine model.

BACKGROUND: To date, the extended Morrow procedure is considered the gold standard treatment for patients with obstructive hypertrophic cardiomyopathy who experience severe symptoms and are unresponsive to medication treatment. We therefore aimed to perform transapical intramyocardial septal microwave ablation to reduce the thickness of the interventricular septum myocardium in a minimally invasive method. METHODS: Fourteen swine were divided to form either a microwave ablation group (n = 7) or a sham group (n = 7). In the microwave ablation group, a transapical microwave antenna was inserted into the septum to ablate each myocardial segment at 40 W for 1 min, while in the sham group, the same operation was performed but without power output. We used echocardiography, electrocardiogram, during the operation. And added computerized tomography, cardiac nuclear magnetic resonance during follow-up. RESULTS: Segment hypokinesis was observed in all swine immediately following ablation. Compared with the sham group, the thickness of ablated segments in the ablation group decreased significantly 1 month post-operation (ablation group, 5.53 ± 1.00 mm vs. 8.03 ± 1.15 mm, respectively, P < 0.01; sham group, 8.40 ± 0.94 mm vs. 8.21 ± 1.09 mm, respectively, P = 0.081), and the outcome was still observed 1 year post-operation (ablation group, 3.36 ± 0.85 mm vs. 8.03 ± 1.15 mm, respectively, P < 0.01). No perforation of the septum was observed during the procedure or follow-up, and no heart failure or sudden cardiac death occurred during postoperative feeding. CONCLUSIONS: Transapical intramyocardial septal microwave ablation can effectively and safely produce a large region of necrosis. This technique can potentially mimic surgical myectomy while avoiding cardiopulmonary bypass and median sternotomy in high-risk hypertrophic obstructive cardiomyopathy patients.

Combined transaortic/transapical left ventricular septal myectomy for subaortic and midventricular obstruction in a paediatric patient.

The patient is a 15-year-old girl who was diagnosed with hypertrophic cardiomyopathy and has been symptomatic due to severe left ventricular outflow tract obstruction. Combined transaortic and transapical left ventricular septal myectomy was performed to relieve the left ventricular outflow tract obstruction and address both subaortic and midventricular gradients.

Predictive value of estimated plasma volume for postoperative hypotension in percutaneous intramyocardial septal radiofrequency ablation treating for hypertrophic obstructive cardiomyopathy.

BACKGROUND: Estimated plasma volume status (ePVS) estimated by the Duarte formula is associated with clinical outcomes in patients with heart failure. It remains unclear the predictive value of the ePVS to the postoperative hypotension (POH) in percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) treating hypertrophic obstructive cardiomyopathy (HOCM). METHODS: Data of HOCM patients who underwent PIMSRA were retrospectively collected. Preoperative ePVS was calculated using the Duarte formulas which derived from hemoglobin and hematocrit ratios. Clinical variables including physical assessment, biological and echocardiographic parameters were recorded. Patients were labeled with or without POH according to the medical record in the hospital. Univariable and multivariable logistic regression were performed to evaluate the association between ePVS and POH. Using different thresholds derived from quartiles and the best cutoff value of the receiver operating characteristic curve, the diagnostic performance of ePVS was quantified. RESULTS: Among the 405 patients included in this study, 53 (13.1%) patients were observed with symptomatic POH. Median (IQR) of ePVS in overall patients was 3.77 (3.27~4.40) mL/g and in patients with POH were higher than those without POH. The ePVS was associated with POH, with the odds ratio of 1.669 (95% CI 1.299 ~ 2.144) per mL/g. After adjusted by potential confounders, ePVS remained independently associated with POH, with the approximate odds ratio in different models. CONCLUSION: The preoperative ePVS derived from the Duarte formulas was independently associated with postoperative hypotension in HOCM patients who underwent PIMSRA and showed prognostic value to the risk stratification of postoperative management. TRIAL REGISTRATION: NCT06003478 (22/08/2023).

A case of hypertrophic cardiomyopathy with previous aortic valve replacement.

We describe a 45-year-old patient who was diagnosed with hypertrophic obstructive cardiomyopathy (HOCM) after the aortic valve replacement surgery. Enlarged left atria, thickened ventricular septum, left ventricular outflow tract stenosis, moderate mitral regurgitation and mild tricuspid regurgitation in the echocardiography were found. We offered the patient the new minimally invasive treatment modality: percutaneous intra-myocardial septal radiofrequency ablation (PIMSRA). We demonstrate the safety and efficacy with pictures. One month after surgery, the patient recovered well with improved symptoms of chest tightness, and no LVOT obstruction or arrhythmia.

Hypertrophic Cardiomyopathy: Preadolescence, Mitral Valve Disease, and Midventricular Obstruction.

Septal myectomy is indicated in patients with obstructive hypertrophic cardiomyopathy (HCM) who have persistent symptoms despite medical therapy, intolerance of medication side effects, or severe resting or provocable gradients. Septal myectomy at high volume centers is safe, with low operative mortality (1%) and low rates of complications such as complete heart block or ventricular septal defect (3% and 0.5%, respectively). Additionally, improved survival following myectomy has been observed when compared to patients with obstructive HCM managed medically or those with nonobstructive HCM. As a longstanding, quaternary referral center for septal myectomy, our institution has built significant experience and expertise in the surgical and medical management of HCM, including atypical HCM, defined as preadolescent patients, those with mitral valve disease, and those with isolated midventricular obstruction. The most important factor of septal myectomy in achieving complete resolution of obstruction and avoiding recurrence is the apical extent of the myectomy trough, which must extend to the septum opposite the papillary muscles. If this cannot be fully achieved via a transaortic exposure, especially in preadolescents and patients with midventricular obstruction, then a transapical approach may be needed. Mitral valve repair is rarely necessary as SAM-mediated MR resolves with adequate myectomy alone, but mitral repair is performed in cases of intrinsic valvular disease. In this manuscript we provide a summary of current operative techniques and outcomes data from our institution on the management of these various categories of HCM.

Remimazolam-based anesthesia in a patient with hypertrophic obstructive cardiomyopathy undergoing radical colorectal cancer surgery: A case report.

BACKGROUND: The goal of anesthesia in patients with hypertrophic obstructive cardiomyopathy (HOCM) is to reduce the risk of left ventricular outflow tract obstruction triggered by anesthetics. Remimazolam is a newly developed anesthetic that has been reported to have superior hemodynamic stability. There have been no reports on the completion of non-cardiac surgery with remimazolam in patients with HOCM. METHODS: Here we report the case of a 49-year-old man diagnosed with hypertrophic obstructive cardiomyopathy who underwent resection of colon cancer with remimazolam and remifentanil anesthesia. A bolus 0.3 mg/kg remimazolam was administered for anesthesia induction, and then adjusted to 2 mg/kg/h to maintain anesthesia. Set the pain threshold index to 50 to auto-control the infusion speed of remifentanil. RESULTS: No hypotension occurred during anesthesia, and norepinephrine was not administered. After conversion to open surgery, the patient's blood pressure elevated and reduced with urapidil and esmolol. CONCLUSION: In this patient with HOCM, remimazolam and remifentanil provided adequate anesthesia for induction and maintenance to complete the right hemicolectomy.

Short time effects of two radiofrequency ablation methods on hypertrophic obstructive cardiomyopathy.

BACKGROUND: Radiofrequency ablation has been applied for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). The two known procedures are percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) and endocardial radiofrequency septal ablation (ERSA). METHODS: This study presents a retrospective analysis of the PIMSRA and ERSA procedures in patients with drug-refractory HOCM. A total of 28 patients participated in the study, with 12 receiving PIMSRA and 16 receiving ERSA. The objective of our study was to compare the short-term effects of these two radiofrequency ablation procedures. RESULTS: At the 30-day follow-up, the PIMSRA group demonstrated a greater reduction in left ventricular outflow tract peak gradient at rest compared to the ERSA group (22.25 [16.72] mmHg versus 47.75 [21.94] mmHg) (p < .01). The values for the PIMSRA group decreased from 99.33 (32.00) mmHg to 22.25 (16.72) mmHg (p < .01), while the ERSA group decreased from 97.75 (30.24) mmHg to 47.75 (21.94) mmHg (p < .01). Only the PIMSRA group exhibited a decrease in mitral regurgitation (MR). The area of MR decreased from 10.13 (4.12) mm2 to 3.65 (2.80) mm2 in the PIMSRA group (p < .01). Additionally, the PIMSRA group experienced reductions in left atrial diameter (LAD) and left ventricular ejection fraction (LVEF)%. The values for LAD changed from 43.58 (7.53) mm to 37.08 (6.92) mm (p = .03), and the values for LVEF% decreased from 65.75 (6.12) pg/mL to 60.83 (4.06) pg/mL (p = .03). CONCLUSION: In terms of the two types of radiofrequency ablation methods used in HOCM, it has been observed that PIMSRA demonstrates a more favorable early treatment effect compared to ERSA.

[Mid-ventricular Hypertrophic Obstructive Cardiomyopathy in a Patient Whose Hemodynamics Were Exacerbated by Forward Shift of the Posterior Leaflet Caused by Mitral Annular Calcification].

A 82-year-old woman came to our hospital because of orthopnea and cardiac cachexia. Echocardiography revealed a pressure gradient of 50 mmHg at the left ventricular outflow tract and that of 78 mmHg at the mid-ventricle. Systolic anterior motion of the mitral leaflet caused by mitral annular calcification and severe mitral regurgitation( MR) were observed. On the basis of the patient's age and poor general conditions, we resected abnormal myocardium on the septum from the outflow tract down to the apex via aortic valve and we left the mitral annular calcification. The pressure gradient in the left ventricle, systolic anterior motion and mitral regurgitation were relieved, and her postoperative course was uneventful. Two years after the surgery, she remains in New York Heart Association( NYHA) class Ⅰ and is well.

Long-term post-transplantation outcomes in patients with hypertrophic cardiomyopathy: Single-center 35-year experience.

BACKGROUND: Heart transplantation (HT) is the only option for most patients with end-stage heart failure and hypertrophic cardiomyopathy (HCM) who fail medical therapy. Data on the long-term outcomes post-transplant in HCM individuals remain scarce. METHODS: We analyzed data of 319 adult patients who underwent HT between 1984 and 2019. Patients were followed for cardiac allograft rejection, cardiac allograft vasculopathy (CAV), death, or re-transplantation. RESULTS: Outcomes of 24 patients with HCM, 160 with ischemic, and 135 with dilated cardiomyopathy were compared. During a mean follow-up of 11.6 ± 7.2 (max 27.8), 16.7 ± 8.2 (max 32.7), and 16.1 ± 9.7 (max 34.6) years after HT in hypertrophic, ischemic, and dilated cardiomyopathy groups, respectively: 10-year survival rate was 67%, 62%, 69%, respectively (p = .04). Post-transplantation, HCM individuals more often than the other two studied groups required prolonged inotropic support (37%, 12%, 17%, respectively, p = .02), temporary mechanical circulatory support (45%, 13%, 14%, respectively, p < .01), and renal replacement therapy immediately post-HT (55%, 19%, 24%, respectively, p < .01). No significant inter-group differences were noted in the 10-year freedom from acute allograft rejection (38%, 46%, 43%, respectively, p = .38) or 10-year freedom from CAV (88%, 78%, 81%, respectively, p = .57). CONCLUSIONS: The long-term post-transplant prognosis of adult patients with hypertrophic cardiomyopathy is favorable despite more challenging immediate post-HT course.

Evolving indications for transcatheter mitral edge-to-edge repair.

Transcatheter mitral edge-to-edge repair (TEER) is an established procedure for managing mitral regurgitation (MR) in high-risk patients. It is effective in treating both primary and secondary MR, as reported in the surgical and interventional literature. Over time, TEER has gained popularity and achieved procedural success in various anatomies. The less invasive nature of TEER, along with its high safety profile and immediate haemodynamic improvement suggest potential benefits in high-risk populations who are not normally included in major trials. These patients, often deemed unsuitable for surgical intervention, are typically managed conservatively, despite accumulating evidence suggesting the potential of clinical improvement by reducing MR through TEER. Examples include post-myocardial infarction MR, patients with hypertrophic obstructive cardiomyopathy and patients experiencing recurrent MR after surgical intervention. This review discusses the utilisation of TEER beyond recognised indications, examining outcomes and limitations in diverse patient populations. Further studies are warranted to evaluate the benefits of TEER in clinical scenarios beyond the current indications.

Resection of hypertrophic papillary muscles and mitral valve replacement in a patient with midventricular hypertrophic obstructive cardiomyopathy - a new approach.

Midventricular hypertrophic obstructive cardiomyopathy (HOCM) is characterized by hypertrophy of the interventricular septum (IVS) and - in rare cases - of the papillary muscles (PM), which subsequently can cause dynamic left ventricular outflow tract obstruction (LVOTO) and severe heart failure symptoms. We report on a rare case of a 44-year-old patient suffering from midventricular HOCM with hypertrophic anterolateral PM and an additional chorda between the PM and the IVS.We describe a new surgical approach via right anterolateral thoracotomy in 3-dimensional (3D) video-assisted minimal-invasive technique with resection of hypertrophic PMs as well as the entire mitral valve-apparatus and valve replacement avoiding septal myectomy and potentially associated complications. After an uneventful procedure clinical symptoms improved from NYHA III-IV at baseline to NYHA 0-I postoperatively and remained stable over a follow-up period of 24 months. Therefore, the presented technique may be considered as a new and alternative approach in patients with hypertrophic PMs and hypertrophic IVS as subtype of midventricular HOCM.

Comparison of Early and Mid-Term Outcomes After Classic and Modified Morrow Septal Myectomy in Patients with Hypertrophic Obstructive Cardiomyopathy.

INTRODUCTION: The aim of our study is to compare the early and mid-term outcomes of patients with hypertrophic obstructive cardiomyopathy who underwent classic and modified Morrow septal myectomy. METHODS: Between 2014 and 2019, 48 patients (24 males; mean age 49.27±16.41 years) who underwent septal myectomy were evaluated. The patients were divided into two groups - those who underwent classic septal myectomy (n=28) and those who underwent modified septal myectomy (n=20). RESULTS: Mitral valve intervention was higher in the classic Morrow group than in the modified Morrow group, but there was no significant difference (P=0.42). Mortality was found to be lower in the modified Morrow group than in the classic Morrow group (P=0.01). In both groups, the mean immediate postoperative gradient was significantly higher than the mean of the 3rd and 12th postoperative months. The preoperative and postoperative gradient difference of the modified Morrow group was significantly higher than of the classic Morrow group (P<0.001). CONCLUSION: Classic Morrow and modified Morrow procedures are effective methods for reducing left ventricular outflow tract obstruction. The modified Morrow procedure was found to be superior to the classic Morrow procedure in terms of reducing the incidence of mitral valve intervention with the reduction of the left ventricular outflow tract gradient.

Myocardial bridging in obstructive hypertrophic cardiomyopathy: a risk factor for myocardial fibrosis.

BACKGROUND: Myocardial bridging (MB) is common in patients with hypertrophic cardiomyopathy (HCM). There are sparse data on the impact of MB on myocardial fibrosis in HCM. This study was designed to evaluate the relationship between MB and myocardial fibrosis in patients with obstructive HCM. METHODS: In this cohort study, retrospective data were collected from a high-volume HCM center. Patients with obstructive HCM who underwent septal myectomy and preoperative cardiac magnetic resonance (CMR) were screened from 2011 to 2018. RESULTS: Finally, 492 patients were included in this study, with an average age of 45.7 years. Of these patients, 76 patients had MB. MB occurred mostly in the left anterior descending artery (73/76). The global extent of late gadolinium enhancement (LGE) was correlated with the degree of systolic compression (r = 0.33, p = 0.003). Multivariable linear regression analysis revealed that the degree of systolic compression was an independent risk factor for LGE (ß = 0.292, p = 0.007). The LGE fraction of basal and mid anteroseptal segments in patients with severe MB (compression ratio ≥ 80%) was significantly greater than that in patients with mild to moderate MB (compression ratio < 80%). During a median follow-up of 28 (IQR: 15-52) months, 15 patients died. Kaplan-Meier analysis did not identify differences in all-cause death (log-rank p = 0.63) or cardiovascular death (log-rank p = 0.72) between patients undergoing MB-related surgery and those without MB. CONCLUSIONS: MB with severe systolic compression was significantly associated with a high extent of fibrosis in patients with obstructive HCM. Concomitant myotomy or coronary artery bypass grafting might provide excellent survival similar to that of patients without MB. Identification of patients with severe MB and providing comprehensive management might help improve the prognosis of patients with HCM.

Treatment Strategies for Hypertrophic Cardiomyopathy: Alcohol Septal Ablation and Procedural Step-by-Step Technique.

Alcohol septal ablation (ASA) is a well-established procedure for septal reduction therapy in patients with obstructive hypertrophic cardiomyopathy, significant at rest or provocable outflow tract gradients, and medically refractory symptoms. This percutaneous approach to relief of obstruction and eventual cardiac remodeling involves the infusion of a small quantity of ethanol into an appropriately targeted septal artery that is feeding the basal septum to create an iatrogenic and controlled focal infarction. Early akinesia is followed by subsequent thinning and remodeling, which widens the outflow tract, reducing or eliminating the obstruction. Historically, the use of ASA was reserved primarily for high-risk surgical candidates; however, more contemporary data suggest similar outcomes in the short-term and long-term safety of the procedure and overall effectiveness in relieving obstructive symptoms when it is performed in broader populations at experienced centers. Therefore, the current guidelines published in 2020 support ASA as a class 1 indication, similar to its open-heart surgical counterpart, surgical myectomy, when no concomitant significant coronary or valve surgical indication exists. This article summarizes contemporary management of patients with hypertrophic cardiomyopathy who were selected for ASA and details procedural methods and outcomes.

Association between postoperative nadir platelet count and postoperative cardiovascular complications following septal myectomy in patients with hypertrophic cardiomyopathy: a retrospective cohort study.

BACKGROUND: Platelet count is associated with cardiovascular risk and mortality in several cardiovascular diseases, but the association of the nadir platelet counts post-septal myectomy with the cardiovascular complication risk in hypertrophic obstructive cardiomyopathy patients remains unclear. METHODS: This retrospective cohort study reviewed all adult patients who underwent septal myectomy at a single tertiary referral center over a 5-year period. Postoperative nadir platelet count was defined as the lowest platelet count in the first 4 postoperative days or until hospital discharge. The composite outcome included cardiovascular death, myocardial infarction, heart failure, malignant arrhythmia, cardiac tamponade, and major bleeding events within 30 days postoperatively. Univariable and multivariable logistic regression and restricted cubic spline models were used to assess the association between postoperative nadir platelet count and the 30-day postoperative cardiovascular complication risk. RESULTS: Among the 113 enrolled patients, 23 (20.4%) developed cardiovascular events within 30 days postoperatively. The incidence of postoperative cardiovascular complications was significantly higher in patients with a nadir platelet count ≤ 99 × 109/L than in those with a nadir platelet count > 99 × 109/L (33.3% vs. 7.1%, crude risk ratio: 4.67, 95% confidence interval: 1.69-12.85, P < 0.001). Multivariable logistic regression revealed that postoperative nadir platelet count was negatively associated with 30-day postoperative cardiovascular complications (adjusted odds ratio: 0.97; 95% confidence interval: 0.95-0.99; P = 0.005) and the association was linear (Pnonlinearity = 0.058) after full adjustment. The association between nadir platelet count and cardiovascular complications within 30 days post-surgery was consistent in all predefined subgroups (Pinteraction > 0.05). CONCLUSION: The postoperative nadir platelet count was significantly associated with the 30-day post-myectomy risk of cardiovascular complications in hypertrophic obstructive cardiomyopathy patients. TRIAL REGISTRATION: This trial was registered at ClinicalTrials.gov (NCT04275544).