Toshinori Yuasa

Mechanism of Recurrent/Persistent Ischemic/Functional Mitral Regurgitation in the Chronic Phase After Surgical Annuloplasty Importance of Augmented Posterior Leaflet Tethering

Background— Surgical annuloplasty can potentially hoist the posterior annulus anteriorly, exaggerate posterior leaflet (PML) tethering, and lead to recurrent ischemic/functional mitral regurgitation (MR). Characteristics of leaflet configurations in late postoperative MR were investigated. Methods and Results— In 30 patients with surgical annuloplasty for ischemic MR and 20 controls, the anterior leaflet (AML) and PML tethering angles relative to the line connecting annuli, posterior and apical displacement of the coaptation and the MR grade were measured by echocardiography before, early after, and late after surgery. Early after surgery, grade of MR and AML tethering generally decreased (P<0.01), whereas PML tethering significantly worsened (P<0.01). Nine of the 30 patients showed recurrent/persistent MR late after surgery. Compared with patients without late MR, those with the MR showed similar reduction in the annular area, significant re-increase in posterior displacement of the coaptation, and progressive worsening in PML tethering (P<0.05) late after surgery in comparison to the early phase. Both preoperative MR and late postoperative MR were significantly correlated with all tethering variables in univariate analysis. Although apical displacement of the coaptation was the primary determinant of preoperative MR (r2=0.60, P<0.0001), increased PML tethering was the primary determinant of late MR (r2=0.75, P<0.0001). Conclusions— Whereas both leaflets tethering is related to preoperative ischemic MR, both leaflets tethering but with predominant contribution from augmented and progressive PML tethering is related to recurrent/persistent ischemic/functional MR late after surgical annuloplasty.

Mechanism of Persistent Ischemic Mitral Regurgitation After Annuloplasty Importance of Augmented Posterior Mitral Leaflet Tethering

Background—We hypothesized that surgical annuloplasty for ischemic mitral regurgitation (MR) that displaces the posterior annulus anteriorly can potentially augment posterior leaflet (PML) tethering, leading to persistent MR. Relationships between leaflet configurations and persistent ischemic MR after the annuloplasty were investigated. Methods and Results—In 31 patients with surgical annuloplasty for ischemic MR and 20 controls, posterior and apical displacement of the leaflet coaptation, the anterior leaflet (AML) and PML tethering angles relative to the line connecting annuli, coaptation length (CL), and the MR grade were quantified before and early after surgery in echocardiographic left ventricular long-axis views. Six of the 31 patients showed persistent MR despite annuloplasty. Compared with patients without persistent MR, those with MR showed no improvement in the left ventricular ejection fraction and systolic volume, similar reduction in the annular area, significant increase in posterior displacement of the coaptation (P<0.01), no improvement in AML tethering, greater worsening in PML tethering (P<0.01), and no increase in the CL. All tethering variables were significantly correlated with both preoperative and postoperative MR in univariate analysis, and reduced CL was the primary independent determinant of both preoperative and postoperative MR. Although increased AML tethering was the primary determinant of the preoperative CL (r2=0.46, P<0.0001), increased PML tethering was the primary determinant afterward (r2=0.60, P<0.0001). Conclusion—Although tethering of both leaflets is the major determinant of ischemic MR before surgical annuloplasty, both leaflets tethering but with predominant and augmented PML tethering is related to persistent ischemic MR after the annnuloplasty.

Left atrium volume index and pathological features of left atrial appendage as a predictor of failure in postoperative sinus conversion

BACKGROUND Previous studies showed that some parameters, including left atrium diameter and left atrium volume index (LAVI), predicted the success of sinus conversion. However, no previous studies have investigated the association of sinus conversion with LAVI and histopathological findings. This study was designed to investigate the relationship among LAVI, pathological assessment, and failure in sinus conversion after surgery for valvular atrial fibrillation (AF). METHODS AND RESULTS A total of 78 patients with left atrium enlargement and valvular AF who underwent maze procedure concomitantly with various cardiac surgeries were classified into one of two groups: those who successfully underwent sinus conversion (Group 1; n=40) and those who did not achieve sinus conversion (Group 2; n=38). Histopathological assessment was performed in 9 cases using tissues derived from the left atrial appendage (LAA). The degree of histopathological change was classified into 1 of 4 grades. LAVI was significantly less in Group 1 than in Group 2 (81 + or - 22 ml/m(2) vs. 122 + or - 49 ml/m(2), p<0.001). Preoperative LAVI predicted 100% failure of sinus conversion after surgery with a cut-off value of 135 ml/m(2). Histopathological analyses clearly showed that the grades for intercellular fibrosis, fatty infiltration, endocardial thickening, and nuclear enlargement/abnormalities were significantly and positively correlated with LAVI (r=0.75, p<0.05; r=0.74, p<0.05; r=0.69, p<0.05; r=0.77, p<0.05, respectively). CONCLUSIONS LAVI associated with histopathological features of the resected LAA is a predictor of failure in sinus conversion following surgical intervention in patients with valvular AF.

Left ventricular global systolic dysfunction has a significant role in the development of diastolic heart failure in patients with systemic hypertension

Regional left ventricular (LV) systolic dysfunction has been identified in diastolic heart failure (DHF). However, the relationship between regional or global LV systolic function and heart failure symptoms in DHF has not been evaluated in detail. The present study evaluates such relationships in patients with systemic hypertension (HT) and DHF. We assessed LV systolic and diastolic function in 220 consecutive patients with systemic HT and in 30 normal individuals (Control) using Doppler echocardiography. Patients with HT were assigned to groups with DHF, asymptomatic diastolic dysfunction (ADD) and no diastolic dysfunction (Simple HT). Ejection fraction in DHF was significantly decreased (63±8%) compared with the Control, Simple HT and ADD groups (67±5, 66±7 and 68±8%, respectively). Isovolumetric contraction time in DHF (70±30 msec) was significantly increased compared with those in the ADD, Simple HT and Control groups (31±17, 31±15 and 30±19 msec, respectively). Mitral annular systolic velocities were significantly decreased in the DHF and ADD groups (6.4±1.5 and 7.2±1.3 cm sec−1, respectively) compared with those in the Simple HT and Control groups (8.5±1.8 and 8.4±3.0 cm sec−1, respectively), and in the DHF group compared with the ADD group. LV global systolic dysfunction has a significant role in the development of heart failure symptoms associated with DHF in patients with systemic HT.

Papillary muscle dysfunction attenuates ischemic mitral regurgitation in patients with localized basal inferior left ventricular remodeling

OBJECTIVES The purpose of this research was to test whether papillary muscle (PM) dysfunction attenuates ischemic mitral regurgitation (MR) in patients with left ventricular (LV) remodeling of a similar location and extent. BACKGROUND Papillary muscle dysfunction could attenuate tethering and MR because of PM elongation. However, variability in the associated LV remodeling, which exaggerates tethering, can influence the relationship between PM dysfunction and MR. METHODS In 40 patients with a previous inferior myocardial infarction but without other lesions, the LV volume, sphericity, PM tethering distance, PM longitudinal systolic strain, and MR fraction were quantified by echocardiography. The patients were divided into two groups: group 1 with significant basal inferoposterior LV bulging but without advanced LV bulging involving other territories, therefore with a similar location and extent of LV remodeling, and group 2 without significant LV bulging. RESULTS The medial PM tethering distance was significantly correlated with the %MR fraction (r2 = 0.64, p < 0.01), and multiple regression analysis identified an increase in the tethering distance as the only independent determinant of the MR fraction in all subjects and also in group 1. The PM longitudinal systolic strain had no significant relationships with MR fraction in all subjects with variable degrees of LV remodeling, but it had a significant inverse correlation with the MR fraction (r2 = 0.33, p < 0.01) in group 1 with LV remodeling of a similar location and extent, indicating that PM dysfunction is associated with less MR. CONCLUSIONS Papillary muscle dysfunction, reducing its longitudinal contraction to induce leaflet tethering, attenuates ischemic MR in patients with basal inferior LV remodeling.

Validity of a Novel Method for Estimation of Low-Density Lipoprotein Cholesterol Levels in Diabetic Patients

Aim: Low-density lipoprotein cholesterol (LDL-C) is routinely estimated using the Friedewald equation [LDL-C(F)]. A novel method for LDL-C [LDL-C(M)] estimation recently proposed by Martin et al. was reported to be more accurate than the Friedewald formula in subjects in the United States. The validity of LDL-C(M) in different races and patients with diabetes mellitus (DM) has not been elucidated. The purpose of this study was to validate the LDL-C(M) estimates in Japanese population with type 2 DM by comparing with LDL-C(F) and directly measured LDL-C [LDL-C(D)]. Methods: Both LDL-C(M) and LDL-C(F) levels were compared against LDL-C(D) measured by selective solubilization method in 1,828 Japanese patients with type 2 DM. Results: On linear regression analysis, LDL-C(M) showed a stronger correlation than that shown by LDL-C(F) (R = 0.979 vs. R = 0.953, respectively) with LDL-C(D). We further analyzed the effect of serum triglyceride (TG) concentrations on the accuracy of LDL-C(F) and LDL-C(M). Although LDL-C levels showed a positive correlation with TG levels, the LDL-C(F) levels tended to show a greater divergence from LDL-C(D) levels than that shown by LDL-C(M) with changes in TG levels. Conclusion: We for the first time demonstrated a more useful measurement of LDL-C levels estimated by Martins method than that estimated by the Friedewald equation in Japanese patients with DM.

No reflow-like pattern in intramyocardial coronary artery suggests myocardial ischemia in patients with hypertrophic cardiomyopathy.

BACKGROUND AND PURPOSE To evaluate intramyocardial coronary flow velocity pattern by transthoracic Doppler echocardiography and its clinical significance in patients with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS In 48 patients with HCM who had angiographically normal coronary artery, coronary flow velocity in the left anterior descending coronary artery (LAD) and intramyocardial coronary artery (IMCA) derived from LAD were evaluated using transthoracic Doppler echocardiography. Two clearly different flow patterns in the IMCA were observed in patients with HCM. Twenty-seven HCM patients (group A) had slow deceleration slope in the IMCA flow (average diastolic deceleration time, 989+/-338; range, 585-1680) and the remaining 21 patients (group B) had steep deceleration slope with diastolic deceleration time <300 ms, resulting in a no reflow-like pattern in the IMCA flow (average diastolic deceleration time, 166+/-67; range, 55-280). There were no significant differences in the clinical characteristics and LAD flow velocity profiles between the two groups. The incidence of cardiovascular symptoms (chest pain or syncope) was significantly higher in group B than in group A (67% vs. 26%, p<0.01). Additionally, exercise-induced ischemia as detected by thallium-201 scintigraphy was significantly more frequent in group B than in group A (6 of 9 (67%) vs. 0 of 9 (0%), p<0.01). CONCLUSIONS Two different intramyocardial coronary flow velocity patterns are observed in patients with HCM using transthoracic Doppler echocardiography. No reflow-like pattern in the IMCA is strongly related to myocardial ischemia in the absence of epicardial coronary artery stenosis, suggesting that coronary microvascular dysfunction may be a causative mechanism.

Attenuated early diastolic interventricular septum bulging by pulmonary hypertension due to later developed aortic regurgitation

A woman was admitted due to dyspnea. She had familial pulmonary arterial hypertension and typical echocardiographic findings including early diastolic bulging of the interventricular septum toward the left ventricular cavity. Her symptoms improved with medication. Five months later, she was hospitalized again due to severe dyspnea. Echocardiography demonstrated aortic valve vegetation and its regurgitation. Echocardiography also showed attenuation of early diastolic compression of the interventricular septum, however, the peak tricuspid regurgitant flow velocity did not improve. It is likely that development of left-sided heart failure attenuated abnormal interventricular septal motion due to pulmonary hypertension.

Usefulness of Tissue Doppler Imaging-Derived Atrial Conduction Time for Prediction of Atrial Fibrillation.

patients were monitored with continuous ECG telemetry for ≥2 weeks following MVS. The current study was able to detect new-onset of AF without fail compared with previous reports.6–8 Secondly, under univariate analysis of prediction for postoperative AF, a degenerative MR, the duration of MR, A-wave peak velocity, PA-TDI duration and preoperative CVP were significant predictors of postoperative AF. Multivariate analysis demonstrated that degenerative MR (95% confidence interval (CI): 1.41–15, P=0.0112) and PA-TDI duration (95% CI: 1.01–1.07, P=0.0048) were significant and independent predictors of postoperative AF. The reason for the poor association of LA volume parameters and postoperative AF in this study was the larger LA volume in both the AF and non-AF groups (LA volume index, AF 58.7±20.6 ml/m2 vs. Non-AF 53.4±16.2 ml/m2 P=0.27). The current results were a little different from previous reports analyzing patients after off-pump CABG11 or AVR.12 Multivariate analysis demonstrated that postoperative AF after ulnerability to atrial fibrillation (AF) associates the atrial condition with the critical number of wavelets and multiple reentrant circuits resulting in delayed intra-atrial conduction.1,2 Total atrial conduction time (TACT), representing the total time required for atrial electrical activation, can be evaluated as the maximal P-wave duration using single-averaged electrocardiogram (SA-ECG), and is reported to be a powerful predictor of AF.3,4 However, this method of measuring TACT is difficult to use in clinical practice because of its time-consuming technique and requirement for special hardware. Merckx et al described an alternative echocardiographic measurement using tissue Doppler imaging (TDI) to estimate TACT. They measured the time from the initiation of atrial depolarization represented by the onset of the P-wave on the 12-lead surface ECG (lead II) until the last atrial depolarization represented by the peak of TDI A’ wave at the left atrial (LA) lateral wall (Figure). They also demonstrated that this TDI-derived atrial conduction time (PA-TDI duration) using echocardiography equipment5 had the best correlation with TACT measured by SA-ECG. Furthermore, PA-TDI duration also enables practical and better prediction of new-onset AF,6 recurrence after AF ablation7 and AF after acute myocardial infarction8 compared with LA volume or other parameters.

Prosthetic tricuspid valve dysfunction assessed by three-dimensional transthoracic and transesophageal echocardiography

A 39-year-old male who had undergone tricuspid valve replacement for severe tricuspid regurgitation was admitted with palpitation and general edema. Two-dimensional (2D) echocardiography showed tricuspid prosthetic valve dysfunction. Additional three-dimensional (3D) transthoracic and transesophageal echocardiography (TEE) could clearly demonstrate the disabilities of the mechanical tricuspid valve. Particularly, 3D TEE demonstrated a mass located on the right ventricular side of the tricuspid prosthesis, which may have caused the stuck disk. This observation was confirmed by intra-operative findings.