Evaluation of fluid field of left ventricle outflow tract in hypertrophic obstructive cardiomyopathy with fluid models based on three-dimensional echocardiography with inverted grey values / 中华超声影像学杂志

Objective:To explore the effect of systolic anterior motion (SAM) of mitral valves on the morphology and function of left ventricular outflow tract (LVOT) in patients with hypertrophic obstructive cardiomyopathy (HOCM) using computer fluid dynamics based on three-dimensional echocardiography with inverted grey values.Methods:A total of 40 patients with hypertrophic cardiomyopathy were divided into SAM group (24 cases) and non SAM group (16 cases) in Renmin Hospital of Wuhan University from April 2016 to October 2019. Two dimensional and three-dimensional echocardiographic data of the patients were collected. The LVOT morphological model was constructed based on the post-processing of three-dimensional echocardiography data, and the LVOT flow field model was constructed based on the time-volume curve of left ventricle. LVOT peak velocity was obtained to assess the agreement with echocardiography measurements. Area of LVOT, average velocity, flow rate and iso-surface area of vortex of different levels were obtained and compared between the two groups.Results:There was a good correlation between cardiac fluid model and echocardiographic measurement ( r=0.943, P<0.01). The Bland-Altman consistency interval was -75.0-111.3, and 92.5% of the points were within the consistency limit. Compared with non-SAM group patients, the peak velocity of LVOT increased, the area of LVOT decreased, the flow rate decreased and the area of vortex increased in SAM patients (all P<0.01). In the SAM group, in 16 patients the double orifice LVOT was observed due to the contact between mitral valve and septum, in 1 patient the single orifice LVOT structure was observed with contact between mitral value and septum, and in 7 patients, single orifice LVOT without contact between mitral value and septum. In SAM patients, compared with single orifice LVOT, patients with double orifice LVOT were observed with higher LVOT velocity, smaller LVOT area and higher vortex area with high level(all P<0.05). Conclusions:Accurate fluid models can be obtained using three-dimensional echocardiography with inverted grey values. In SAM patients, contact between mitral valve and septum leads to the formation of double orifice structure and the increase of vortex level in LVOT.

Surgical treatment for hypertrophic obstructive cardiomyopathy with moderate-to-severe mitral regurgitation through right mini-thoracotomy / 中国胸心血管外科临床杂志

@#Objective    To explore the effect and safety of surgical treatment for hypertrophic obstructive cardiomyopathy (HOCM) with mitral regurgitation (MR) through right mini-thoracotomy. Methods    From January 2008 to June 2018, 54 patients with HOCM and moderate-to-severe MR underwent modified Morrow procedure and edge-to-edge mitral valvuloplasty through right mini-thoracotomy, including 31 males and 23 females, with an average age of 47.1±12.6 years. All patients had systolic anterior motion (SAM) phenomenon. Preoperative left ventricular outflow tract pressure gradient (LVOTPG) was 93.6±32.8 mm Hg, interventricular septum thickness (IVST) was 24.8±2.8 mm. Results    Surgeries in all patients were completed successfully. No early death or interventricular septal perforation occurred. One (1.9%) patient received permanent pacemaker implantation due to the complete atrial-ventricular block. At discharge, postoperative LVOTPG (18.1±6.2 mm Hg) and IVST (14.5±2.1 mm) were significantly decreased compared with the preoperative values (P<0.05). No MR or SAM was observed in all patients. The follow-up time was 6-132 months, and during this period, no death, MR or SAM occurred. The average LVOTPG was 19.4±5.7 mm Hg, and the average IVST was 14.2±1.5 mm. Conclusion    Morrow procedure and edge-to-edge mitral valvuloplasty through right mini-thoracotomy is a safe and effective method for treatment of HOCM with moderate-to-severe MR.

Left ventricular outflow tract obstruction following aortic valve replacement: A review of risk factors, mechanism, and management

The presence of dynamic left ventricular outflow tract obstruction (LVOTO) can complicate the postoperative course of patients undergoing surgical aortic valve replacement (AVR). The phenomenon of LVOTO is a consequence of an interplay of various pathoanatomic mechanisms. The prevailing cardiovascular milieu dictates the hemodynamic significance of the resultant LVOTO in addition to the anatomical risk factors. A thorough understanding of the predisposing factors, mechanism, and hemodynamic sequel of the obstruction is pivotal in managing these cases. A comprehensive echocardiographic examination aids in risk prediction, diagnosis, severity characterization, and follow-up of management efficacy in the setting of postoperative LVOTO. The armamentarium of management modalities includes conservative (medical) and surgical options. A stepwise approach should be formulated based on the physiological and anatomical substrates predisposing to LVOTO. The index phenomenon occurs more frequently than appreciated and should be considered when the post-AVR patients exhibit hemodynamic instability unresponsive to conventional supportive measures. The present article provides an overview of various peculiarities of this under-recognized phenomenon in the context of the perioperative management of patients undergoing AVR.

A Case of Mitral Valve Revision Surgery Necessitated by Systolic Anterior Motion of the Mitral Valve after Initial Repair / 日本心臓血管外科学会雑誌

<p>Systolic anterior motion (SAM) is a common complication of mitral valve repair surgery and occasionally requires further treatment. A 56-year-old woman with severe mitral regurgitation accompanied by posterior leaflet prolapse underwent mitral valve plasty including hour-glass-shaped resection, chordal replacement, and interrupted commissural band annuloplasty. The mitral valve was exposed via a right-sided left atriotomy. We found a large thick P2-3 scallop (27 mm in height) with ruptured and elongated chordae. After repair, transesophageal echocardiography (TEE) revealed SAM of the anterior mitral leaflet and severe mitral regurgitation upon weaning from the cardiopulmonary bypass. Although catecholamine was discontinued and volume loading applied, the SAM did not improve. We decided to revise the mitral plasty. Therefore, although the height of the P3 scallop after resection remained 17 mm, neochordae were placed once more on the basal side of the posterior leaflet, and the leaflet was shortened by placing a continuous suture near the annulus. This reduced the height of the posterior leaflet and moved the co-aptation line posteriorly. After this repair, TEE showed that the SAM had disappeared. Thus, repositioning the neochordae and shortening the posterior leaflet by applying a continuous suture effectively and rapidly eliminated the problem.</p>

A Case of Mitral Valve Replacement for Left Ventricular Outflow Tract Obstruction due to Abnormal Papillary Muscle / 日本心臓血管外科学会雑誌

A 72-year-old man, in whom hypertrophic cardiomyopathy (HCM) had been treated with medication for 4 years, complained of general fatigue and mild dyspnea on effort. Transthoracic and transesophageal echocardiography revealed diffuse left ventricular (LV) hypertrophy and LV obstruction from the mid-portion to the outflow tract with a peak pressure gradient of 94 mmHg. Additionally, anterior displacement of the abnormal, hypertrophied anterior papillary muscle (PM) and restricted motion of the anterior mitral leaflet, caused by the shortened chordae arising from the abnormal PM, were found. Furthermore, during the systolic phase, the abnormal, hypertrophied anterior PM was shifted to the septal side, causing LV obstruction with systolic anterior motion of the mitral leaflet. The diagnosis was HCM with LV obstruction due to abnormal PM. Mitral valve replacement (MVR) using a mechanical valve and excision of the abnormal PM was performed. His postoperative course was uneventful, and he was discharged on the 14th postoperative day. Postoperative echocardiography revealed no residual obstruction and no pressure gradient in the LV, indicating that complete release of the LV obstruction had been accomplished. In cases of HCM with LV obstruction due to an abnormal mitral subvalvular apparatus, transaortic septal myectomy may not always be an effective procedure. Therefore, we propose that MVR with excision of the PM should be considered one of the useful surgical procedures for such cases.

Hypertrophic cardiomyopathy: Part 1 - Introduction, pathology and pathophysiology.

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease with many genotype and phenotype variations. Earlier terminologies, hypertrophic obstructive cardiomyopathy and idiopathic hypertrophic sub‑aortic stenosis are no longer used to describe this entity. Patients present with or without left ventricular outflow tract (LVOT) obstruction. Resting or provocative LVOT obstruction occurs in 70% of patients and is the most common cause of heart failure. The pathology and pathophysiology of HCM includes hypertrophy of the left ventricle with or without right ventricular hypertrophy, systolic anterior motion of mitral valve, dynamic and mechanical LVOT obstruction, mitral regurgitation, diastolic dysfunction, myocardial ischemia, and fibrosis. Thorough understanding of pathology and pathophysiology is important for anesthetic and surgical management.

Septal Myectomy and Mitral Valve Replacement for Hypertrophic Obstructive Cardiomyopathy Accompanied by Severe Mitral Regurgitation / 日本心臓血管外科学会雑誌

Septal myectomy and mitral valve surgery are performed for the treatment of hypertrophic obstructive cardiomyopathy (HOCM) ; however, there is a debate as to which is the better option. In this paper, we report on the eventless postoperative course of a patient who underwent septal myectomy and mitral valve replacement simultaneously to treat HOCM accompanied by severe mitral regurgitation. A 75-year-old woman was referred to our department for severe mitral regurgitation accompanied by exertional dyspnea; we observed systolic anterior motion of the anterior mitral leaflet and a left ventricular outflow tract pressure gradient of 130 mmHg that was not decreased by DDD pacing. A 15×6×15-mm rectangular parallele pipe-shaped section of the hypertrophied basal septum was resected via a transaortic approach. In addition, mitral valve replacement with a 25-mm SJM was performed during the same procedure, as lesions were observed in the mitral valve. After surgery, the left ventricular outflow tract pressure gradient decreased by 12.5 mmHg. Necessary and sufficient resection of the hypertrophied basal septum, after careful preoperative and intraoperative evaluation of the extent of myocardial resection and mitral valve lesions is important for improving left ventricular outflow tract pressure gradient in HOCM. Mitral valve replacement should also be performed, if necessary, to treat mitral valve lesions.

Left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve in patient with pericardial effusion caused by ascending aortic dissection: A case report / 대한마취과학회지

Left ventricular outflow tract (LVOT) obstruction with systolic anterior motion (SAM) of mitral valve is not only limited to patients with hypertrophic cardiomyopathy. A diagnosis of LVOT obstruction with SAM is important because conventional inotropic support may potentially aggravate hemodynamic deterioration. We present a case of LVOT obstruction with SAM in a patient who underwent an emergent surgery for ascending aortic dissection with pericardial effusion. The patient showed refractory hypotension after standard pharmacologic interventions during induction of anesthesia. Transesophageal echocardiography (TEE) revealed LVOT obstruction with SAM and it was managed appropriately under the guidance of TEE. Intraoperative TEE can play an important role in diagnosis and management of LVOT obstruction with SAM caused by pericardial effusion.

Validation of a decision-making strategy for systolic anterior motion following mitral valve repair.

Low cardiac output syndrome and hypotension are dreadful consequences of systolic anterior motion (SAM) after a mitral valve (MV) repair. The management of SAM in the operating room remains controversial. We validate a recently suggested two-step management method and classification of this complication. This was a teaching hospital-based observational study. We validated a novel two-step conservative management method, consisting in intravascular volume expansion and discontinuation of inotropic drugs (step 1), and increasing the afterload by ascending aorta manual compression while administering esmolol e.v. (step 2). We also validate a novel classification of SAM: easy-to-revert (responding to step 1), difficult-to-revert (responding to step 2), or persistent. Fifty patients had an easy-to-revert while 26 had a difficult-to-revert SAM; 4 patients had a persistent condition (promptly diagnosed through our decisional algorithm) and underwent an immediate second pump run to repeat the mitral repair surgery. We confirmed that SAM after a repair of a degenerative MV is common and validated a simple two-step conservative management method that allows to clearly identify those few patients who require immediate surgical revision.

Perioperative Hypotension due to Systolic Anterior Motion of the Mitral Valve with Left Ventricular Outflow Track Obstruction during Off-Pump Coronary Artery Bypass Surgery: A case report / 대한마취과학회지

Systolic anterior motion of the mitral valve (SAM) is well known in the concentric left ventricular hypertrophy or post mitral valvuloplasty. However, SAM has not been reported in Off-pump coronary artery bypass surgery (OPCAB). Preoperatively, SAM in combination with a left ventricular outflow tract obstruction leads to severe cardiovascular destabilization. Moreover, a diagnosis of SAM is very important because the administration of conventional therapy to hypotension can aggravate SAM. We report a patient with un-identified left ventricular wall hypertrophy or mitral valve regurgitation, who was diagnosed with SAM by TEE during OPCAB. This report describes the diagnostic and therapeutic strategies for the perioperative management of SAM.

Relationship between Systolic Anterior Motion of the Mitral Valve and the Left Ventricular Outflow Pressure Gradient in Patients with Hypertrophic Obstructive Cardiomyopathy

To analyze the effects of the characteristics of the systolic anterior motion(SAM) of the mitral valve on the left ventricular outflow pressure gradient and to determine the relation between the anatomical characteristics of the left ventricle and the left ventricular outflow pressure gradient, mitral valve and left ventricular M mode echocardiogram and continuous wave Doppler echocardiogram of the left ventricular outflow tract were recorded in 7 patients with hypertrophic obstructive cardiomyopathy(HOCM), aged 19 to 66 years(mean 37 years). Mitral-septal distance at the closest apposition(S-SAM;1.1+/-2mm), duration of mitral-septal apposition(89+/-20 msec), time interval from the peak of the R-wave to initial apposition of the mitral valve against the interventricular septum(R-SAM interval ; 222+/-32 msec) and left ventricular posterior wall thickness(LVPWT; 1.1+/-0.5mm) were observed on mitral valve and left ventricular M-mode echocardiograms and peak flow velocity in the left ventricular outflow(V-LVOT; 3.5+/-1.5 m/sec) was measured from the Doppler echocardiograms of the left ventricular outflow tract. V-LVOT was correlated significantly with degree of mitral-septal apposition(r=-0.70, p<0.05), duration of mitral-septal apposition(r=0.74, P<0.05), R-SAM interval(r=-0.80, p<0.05) and LVPWT(r=0.78, p<0.05). These results suggest that the closer apposition of mitral valve against interventricular septum, the more prolonged mitral-septal apposition, the earlier onset of SAM of the mitral valve and the thicker the left ventricular posterior wall, the more increase the LV outflow pressure gradient in HOCM.