K. Kadappu

Changes in left atrial volume in diabetes mellitus: more than diastolic dysfunction?

AIM To evaluate left atrial (LA) volume and function as assessed by strain and strain rate derived from 2D speckle tracking and their association with diastolic dysfunction (DD) in patients with diabetes mellitus (DM). METHODS AND RESULTS Seventy three patients with DM were compared with age- and gender-matched normal controls; 30 patients with DM alone were compared to those with hypertension (HT) alone. The maximum LA volume, traditional measures of atrial function, 2D strain and strain rate were analysed. The LA indexed volume (LAVI) was larger in DM group than that in normal controls (38.2 ± 9.9 vs. 20.5 ± 4.8 ml/m(2), P< 0.0001), as well as in DM alone compared with hypertensive patients (33.9 ± 10 vs. 25.7 ± 8 ml/m(2), P< 0.0001). Global strain was significantly reduced in the DM group compared with that in normal controls (22.5 ± 8.67 vs. 30.6 ± 8.27%; P< 0.0001) but was similar with HT. There was a weak correlation between LAVI and global strain with increasing grades of DD (r= 0.439, P< 0.0001 and r= - 0.316, P< 0.0001, respectively) in the diabetic group. However, there was no significant difference in LAVI between these groups. A logistic regression analysis for predictors of LAVI demonstrated that only diabetes was a determinant of LAVI. Patients with diabetes showed a significant reduction in global strain compared with normal controls but no difference with increasing grades of diastolic function. CONCLUSIONS LA enlargement in DM is independent of associated HT and diastolic function. LA enlargement is associated with LA dysfunction as evaluated by 2D strain. It is likely that a combination of DD and a diabetic atrial myopathy contribute to LA enlargement in patients with DM.

Prognostic implications of left atrial volume index in patients in sinus rhythm.

The maximum left atrial volume index (LAVI) has been shown to be of prognostic values, but previous studies have largely been limited to older patients with specific cardiovascular conditions. We examined the independent prognostic values of LAVI in a large unselected series of predominantly younger patients in sinus rhythm followed up for a long period. We evaluated 483 consecutive patients (mean age 47.3 years) using transthoracic echocardiography. The median LAVI was 24 ml/m(2). A primary combined end point of cardiovascular death, stroke, heart failure, myocardial infarction, and atrial fibrillation was sought. We had complete follow-up data for 97.3% of the 483 patients. During a median follow-up of 6.8 years, 86 patients (18.3%) reached the primary end point. Older age, male gender, diabetes, hypertension, hypercholesterolemia, chronic renal failure, a history of myocardial infarction or stroke, a mitral E deceleration time of </=150 ms, and LAVI of >/=24 ml/m(2) were univariate predictors of the primary end point. Event-free survival was significantly lower for patients with a LAVI of >/=24 ml/m(2). Age, a history of stroke, hypertension, chronic renal failure, and male gender were independent clinical predictors. A LAVI of >/=24 ml/m(2) was the only independent echocardiographic predictor (hazard ratio 1.72, 95% confidence interval 1.34 to 2.13, p = 0.018), with the chi-square of the Cox model increased significantly with the addition of the LAVI (p <0.001). The LAVI independently predicted an increased risk of cardiovascular death, heart failure, atrial fibrillation, stroke, or myocardial infarction during a median follow-up of 6.8 years. In conclusion, the prognostic values were incremental to the clinical risks and were valid in a younger, general patient population.

Comparison of Myocardial Tissue Velocities Measured by Two-Dimensional Speckle Tracking and Tissue Doppler Imaging

Myocardial velocities have prognostic implications, and transmitral E wave to mitral annular early diastolic tissue velocity ratio (E/Em) is utilized to estimate left ventricular (LV) end-diastolic pressure (EDP). There are no reference values for 2-dimensional (2D) speckle tracking myocardial velocities (S2D, E2D, A2D), and it is unknown if they are comparable with color tissue Doppler imaging (TDI). Predictors of E/E2D ratios are unknown and E/E2D has not been validated with LVEDP. The myocardial velocities of 142 subjects were measured by TDI and 2D speckle tracking. Mean E/Em and E/E2D were calculated as transmitral E wave to mean 6 basal early diastolic myocardial velocities using TDI and 2D speckle tracking respectively, and compared with LVEDP during catheterizations (n = 20). Mean E2D was lower but mean S2D and A2D were higher than TDI (all p <0.001). When TDI sample volume was tracked throughout the cardiac cycle, this directional difference was no longer apparent with S2D, E2D, and A2D higher than TDI (all p <0.05). Age, systolic blood pressure, LV ejection fraction, and mean S2D were independent correlates of E/E2D. Receiver-operator characteristic analysis showed E/E2D (p = 0.03), not E/Em, identified elevated LVEDP (> or =12 mm Hg). E/E2D of 11.6 had 83% sensitivity and 70% specificity to predict elevated LVEDP. In conclusion, TDI and 2D speckle tracking myocardial velocities are not comparable due to angle independency and ability for tissue tracking with the latter. LV systolic function, age, and afterload are independent correlates of E/E2D. Only E/E2D identifies elevated LVEDP, and an E/E2D of 11.6 has the optimal sensitivity and specificity.

Tissue Doppler Imaging in Echocardiography: Value and Limitations

Tissue Doppler imaging (TDI) is a useful echocardiographic technique to evaluate global and regional myocardial systolic as well as diastolic function. It can also be used to quantify right ventricular and left atrial function. Recent studies have demonstrated its utility as a diagnostic as well as prognostic tool in different cardiac conditions including coronary artery disease, heart failure (both systolic and diastolic), valvular heart disease, cardiomyopathies as well as constrictive pericarditis. TDI measurements are also helpful to identify patients who will benefit from cardiac resynchronisation therapy. Even though it is reproducible and relatively easy to obtain, it is underutilised in routine clinical practice. TDI is readily available on most commercially available echocardiographic systems, and we recommend that TDI be used for routine clinical echocardiographic evaluation of patients.

Outcomes of Coronary Revascularization (Percutaneous or Bypass) in Patients With Diabetes Mellitus and Multivessel Coronary Disease

Clinical outcomes in patients with diabetes mellitus and multivessel disease (MVD) undergoing coronary revascularization have not been extensively evaluated, we sought to examine outcomes in a diabetic cohort of 195 consecutive patients with MVD characterized by SYNTAX scores (SSs) undergoing nonrandomized revascularization, 102 (52%) by percutaneous intervention (PCI) and 93 (48%) by coronary artery bypass grafting (CABG) at Liverpool Hospital (Sydney, Australia) from June 2006 to March 2010. Clinical outcomes were assessed at a median term of 14 months. The overall median SS was 44, with significantly higher SSs in CABG- than PCI-treated patients (48 vs 39, p <0.0001). There was a similar incidence of all-cause death, nonfatal myocardial infarction and stroke in PCI- and CABG-treated patients (6.1% vs 8.3%, p = 0.383; 12% vs 4.9%, p = 0.152; 3.1% vs 3.5%, p = 0.680 respectively). However, the rates of target vessel revascularization and major adverse coronary and cerebral event were significantly higher in PCI-treated patients than in those undergoing CABG (20% vs 1.2%, p <0.0001; 29% vs 15%, p = 0.034). Despite a much higher SS, patients who underwent PCI achieved comparable outcomes at 1 year to those with diabetes mellitus and a SS ≥ 33 as reported in the SYNTAX trial. In conclusion, in this single-center nonrandomized observational study, coronary revascularization by PCI is associated with increased major adverse coronary and cerebral events at 1-year follow-up, predominantly driven by a high rate of target vessel revascularization. Thus, CABG should remain the revascularization procedure of choice for diabetic patients with MVD and high SSs.

Evaluation of Troponin T Criteria for Periprocedural Myocardial Infarction in Patients With Acute Coronary Syndromes

In patients with acute coronary syndromes undergoing percutaneous coronary intervention (PCI), the diagnosis of periprocedural myocardial infarction is often problematic when the pre-PCI levels of cardiac troponin T (TnT) are elevated. Thus, we examined different TnT criteria for periprocedural myocardial infarction when the pre-PCI TnT levels were elevated and also the associations between the post-PCI cardiac marker levels and outcomes. We established the relation between the post-PCI creatine kinase-MB (CKMB) and TnT levels in 582 patients (315 with acute coronary syndromes and 272 with stable coronary heart disease). A post-PCI increase in the CKMB levels to 14.7 μg/L (3 × the upper reference limit [URL] in men) corresponded to a TnT of 0.23 μg/L. In the 85 patients with acute coronary syndromes and normal CKMB, but elevated post peak TnT levels before PCI (performed at a median of 5 days, interquartile range 3 to 7), the post-PCI cardiac marker increases were as follows: 21 (24.7%) with a ≥ 20% increase in TnT, 10 (11.8%) with an CKMB level >3 × URL, and 12 (14%) with an absolute TnT increase of >0.09 μg/L (p <0.005 for both). In the patients with stable coronary heart disease and post-PCI cardiac markers > 3× URL compared to those without markers elevations, the rate of freedom from death or nonfatal myocardial infarction was 88% for those with TnT elevations versus 99% (p <0.001, log-rank) and 84% for those with CKMB elevations versus 98% (p <0.001, log-rank). Of the patients with acute coronary syndromes, the post-PCI marker levels did not influence the outcomes. In conclusion, in patients with acute coronary syndromes and elevated TnT levels undergoing PCI several days later, ≥20% increases in TnT were more common than absolute increments in the TnT or CKMB levels of >3× URL. Also, periprocedural cardiac marker elevations in patients with acute coronary syndromes did not have prognostic significance.

Chronic kidney disease is independently associated with alterations in left atrial function.

Chronic kidney disease (CKD) is associated with increased cardiovascular morbidity and mortality; hence detection of early cardiovascular involvement in CKD is important to prevent future adverse cardiovascular events. Left atrial (LA) enlargement and dysfunction has been reported in end stage renal disease. However, there is a paucity of published data regarding the evaluation of LA function in CKD using noninvasive imaging parameters. In this study, we evaluated biplane LA volume as well as LA function (LA global systolic strain (GS) and strain rate [SR]) in stage 3 CKD patients (eGFR 30–59 mL/min per 1.73 m2) to determine if LA function parameters are more significantly altered by the presence of CKD in addition to changes due to hypertension alone.

Lung cancer mimicking left atrial mass.

Cardiac involvement in lung cancer is found in up to 25% of autopsy cases. However, despite the considerable mortality and morbidity associated with cardiac metastasis, antemortem diagnosis is unusual. A rare case of lung cancer presenting as a left atrial mass is reported.

Evaluation of a Policy of Selective Drug-eluting Stent Implantation for Patients at High Risk of Restenosis

Drug-eluting stent (DES) deployment during percutaneous coronary intervention (PCI) has reduced target-vessel revascularisation rates (TVR). The selective use of DES in patients at highest risk of restenosis may allay concerns about universal compliance of dual antiplatelet therapy for one year, and potentially reduce costs. If this strategy achieved acceptably low TVR rates, such an approach could be attractive. Late clinical outcomes were examined in 2115 consecutive patients (mean age 63±12 years, 75% male, 22% diabetics) who underwent PCI in the first three years from October 2003, after commencing the following selective criteria for DES use: left main stenosis; ostial lesions of major epicardial arteries; proximal LAD lesions; lesions≥20mm in length with vessel diameter≤3.0mm; lesions in vessels≤2.5mm; diabetics with vessel(s)≤3.0mm; and in-stent restenosis. Among patients undergoing PCI, 2075 (98%) patients received stents (29%≥1 DES and 71% bare metal stent [BMS]), and among those who received DES, there was a 92% compliance with these criteria. There were no differences in clinical outcomes between the two stent groups except for definite stent thrombosis, which occurred in 2% after DES, and 0.6% after BMS at one year (p=0.002). With BMS, large coronary arteries (≥3.5mm), intermediate (3-3.49mm) and small arteries (<3mm) in diameter had a TVR rate at one year of 3.6%, 7.2% and 8.2% respectively (p=0.005). It is possible to use selective criteria for DES while maintaining low TVR rates. The TVR rate with BMS was low in those with stent diameters≥3.5mm. The higher DES stent thrombosis rate reflects first generation DES use, though whether routine second generation DES use reduces these rates needs confirmation.

Bilateral coronary - pulmonary fistulae, diagnosed by transoesophageal echocardiogram

Bilateral coronary artery fistulae to pulmonary artery is a rare condition. We diagnosed this condition by transoesophageal echocardiogram and successfully treated with surgery.