Julie Mundy

Incremental Value of Strain Rate Analysis as an Adjunct to Wall-Motion Scoring for Assessment of Myocardial Viability by Dobutamine Echocardiography A Follow-Up Study After Revascularization

Background— Assessment of myocardial viability based on wall-motion scoring (WMS) during dobutamine echocardiography (DbE) is difficult and subjective. Strain-rate imaging (SRI) is quantitative, but its incremental value over WMS for prediction of functional recovery after revascularization is unclear. Methods and Results— DbE and SRI were performed in 55 stable patients (mean age, 64±10 years; mean ejection fraction, 36±8%) with previous myocardial infarction. Viability was predicted by WMS if function augmented during low-dose DbE. SR, end-systolic strain (ESS), postsystolic strain (PSS), and timing parameters were analyzed at rest and with low-dose DbE in abnormal segments. Regional and global functional recovery was defined by side-by-side comparison of echocardiographic images before and 9 months after revascularization. Of 369 segments with abnormal resting function, 146 showed regional recovery. Compared with segments showing functional recovery, those that failed to recover had lower low-dose DbE SR, SR increment (ΔSR), ESS, and ESS increment (ΔESS) (each P<0.005). After optimal cutoffs for the strain parameters were defined, the sensitivity of low-dose DbE SR (78%, P=0.3), ΔSR (80%, P=0.1), ESS (75%, P=0.6), and ΔESS (74%, P=0.8) was better though not significantly different from WMS (73%). The specificity of WMS (77%) was similar to the SRI parameters. Combination of WMS and SRI parameters augmented the sensitivity for prediction of functional recovery above WMS alone (82% versus 73%, P=0.015; area under the curve=0.88 versus 0.73, P<0.001), although specificities were comparable (80% versus 77%, P=0.2). Conclusions— The measurement of low-dose DbE SR and ΔSR is feasible, and their combination with WMS assessment improves the sensitivity of viability assessment with DbE.

Functional and prognostic implications of left ventricular contractile reserve in patients with asymptomatic severe mitral regurgitation

Objective: To evaluate contractile reserve (CR) determined by exercise echocardiography in predicting clinical outcome and left ventricular (LV) function in asymptomatic severe mitral regurgitation (MR). Design: Cohort study. Setting: Regional cardiac centre. Patients and outcome measures: LV volumes and ejection fraction (EF) were measured at rest and after stress in 71 patients with isolated MR. During follow up (mean (SD) 3 (1) years), EF and functional capacity were serially assessed and cardiac events (cardiac death, heart failure, and new atrial fibrillation) were documented. Results: CR was present in 45 patients (CR+) and absent in 26 patients (CR−). Age, resting LV dimensions, EF, and MR severity were similar in both groups. Mitral surgery was performed in 19 of 45 (42%) CR+ patients and 22 of 26 (85%) CR− patients. In patients undergoing surgery, CR was an independent predictor of follow up EF (p  =  0.006) and postoperative LV dysfunction (EF < 50%) persisted in five patients, all in the CR− group. Event-free survival was lower in surgically treated patients without CR (p  =  0.03). In medically treated patients, follow up EF was preserved in those with intact CR but progressively deteriorated in patients without CR, in whom functional capacity also deteriorated. Conclusions: Evaluation of CR by exercise echocardiography may be useful for risk stratification and may help to optimise the timing of surgery in asymptomatic severe MR.

Assessment of Myocardial Viability at Dobutamine Echocardiography by Deformation Analysis Using Tissue Velocity and Speckle-Tracking

OBJECTIVES Comparison of myocardial tissue-velocity imaging (TVI) and speckle-tracking echocardiography (STE) for prediction of viability at dobutamine echocardiography (DbE). BACKGROUND Use of TVI-based strain imaging during DbE may facilitate the prediction of myocardial viability but has technical limitations. STE overcomes these but requires evaluation for prediction of viability. METHODS We studied 55 patients with ischemic heart disease and left ventricular systolic dysfunction (left ventricular ejection fraction <0.45) who were undergoing DbE for assessment of myocardial viability and who subsequently underwent myocardial revascularization. TVI was used to measure longitudinal end-systolic strain (longS) and peak systolic strain rate (SR) at rest and at low-dose dobutamine (LDD). Longitudinal, radial, and circumferential strain and strain rate were measured with STE. Segmental functional recovery was defined by improved wall-motion score on side-by-side comparison of echocardiographic images before and 9 months after revascularization and areas under the receiver operator characteristic curves were used to compare methods. RESULTS Of the 375 segments with abnormal resting function, 154 (41%) showed functional recovery. Only circumferential resting and low-dose STE strain and low-dose longitudinal strain and SR predicted functional recovery independent of wall-motion analysis. Among different strain parameters, only TVI-based longitudinal end-systolic strain and peak systolic SR at LDD had incremental value over wall-motion analysis (areas under the receiver operator characteristic curves of 0.79, 0.79, and 0.74, respectively). STE measurements of strain and SR identified viability only in the anterior circulation, whereas TVI strain and SR accurately identified viability in both anterior and posterior circulations. CONCLUSIONS Combination of TVI or STE methods with DbE can predict viability, with TVI strain and SR at LDD being the most accurate. TVI measures can predict viability in both anterior and posterior circulations, but STE measurements predict viability only in the anterior circulation.

Plasma acetate, gluconate and interleukin-6 profiles during and after cardiopulmonary bypass: a comparison of Plasma-Lyte 148 with a bicarbonate-balanced solution

IntroductionAs even small concentrations of acetate in the plasma result in pro-inflammatory and cardiotoxic effects, it has been removed from renal replacement fluids. However, Plasma-Lyte 148 (Plasma-Lyte), an electrolyte replacement solution containing acetate plus gluconate is a common circuit prime for cardio-pulmonary bypass (CPB). No published data exist on the peak plasma acetate and gluconate concentrations resulting from the use of Plasma-Lyte 148 during CPB.MethodsThirty adult patients were systematically allocated 1:1 to CPB prime with either bicarbonate-balanced fluid (24 mmol/L bicarbonate) or Plasma-Lyte 148. Arterial blood acetate, gluconate and interleukin-6 (IL-6) levels were measured immediately before CPB (T1), three minutes after CPB commencement (T2), immediately before CPB separation (T3), and four hours post separation (T4).ResultsAcetate concentrations (normal 0.04 to 0.07 mmol/L) became markedly elevated at T2, where the Plasma-Lyte group (median 3.69, range (2.46 to 8.55)) exceeded the bicarbonate group (0.16 (0.02 to 3.49), P < 0.0005). At T3, levels had declined but the differential pattern remained apparent (Plasma-Lyte 0.35 (0.00 to 1.84) versus bicarbonate 0.17 (0.00 to 0.81)). Normal circulating acetate concentrations were not restored until T4. Similar gluconate concentration profiles and inter-group differences were seen, with a slower T3 decay. IL-6 increased across CPB, peaking at T4, with no clear difference between groups.ConclusionsUse of acetate containing prime solutions result in supraphysiological plasma concentrations of acetate. The use of acetate-free prime fluid in CPB significantly reduced but did not eliminate large acetate surges in cardiac surgical patients. Complete elimination of acetate surges would require the use of acetate free bolus fluids and cardioplegia solutions.Trial registrationAustralia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000267055

Risk Factors and Management Approach for Deep Sternal Wound Infection After Cardiac Surgery at a Tertiary Medical Centre

BACKGROUND Deep sternal wound infection (DSWI) is a rare but severe complication following cardiac surgery. Our study investigated the risk factors and treatment options for patients who developed DSWI at our institution between May 1988 and April 2008. METHOD Data was collected prospectively in a database and information on demographics reviewed retrospectively on 5649 patients who underwent cardiac surgery during this period. RESULTS The incidence of DSWI was 34/5649 (0.6%). These patients were older (mean age 66.1 vs. 64.5), more likely to die (in hospital mortality 11.8% vs. non DSWI group 1.8%) and had longer hospital stays (DSWI group mean stay 25 days vs. non DSWI group 9 days). Using Fishers exact test the risk predictors for DSWI determined at our institution included diabetes managed with oral medications (p=0.021), previous cardiac surgery (p=0.038), BMI≥30 (p=0.041), LVEF≤30 (p=0.010), IABP usage (p=0.028) and homologous blood usage (p<0.001). Most commonly bilateral pectoralis major muscle flap (BPMMF) was used for treatment of DSWI (11/30, 36.7%). CONCLUSION Ultimately our data was comparable to published data in the literature on known risk predictors.

Early and mid-term outcomes following surgical management of infective endocarditis with associated cerebral complications: a single centre experience

BACKGROUND Surgical management of patients with infective endocarditis (IE) who have suffered preoperative cerebrovascular complications remains controversial. This study evaluates the impact of timing from stroke to valvular surgery on the early and mid-term neurological sequelae, functional status and quality of life in this high-risk group of patients with IE. METHOD Data on 13/108 (12%) patients with IE who suffered cerebrovascular complications during the period 1998-2009 was prospectively collected. Mean follow-up was 37.2 months (100% complete). RESULTS Three of 13 (23%) suffered haemorrhagic stroke, 10/13 (77%) had embolic events (nine, stroke; one, TIA). The clinical diagnosis was made by a neurologist in 6/13 (46%) and confirmed in all by CT scan. Twelve of 13 had motor deficit involving MCA territory. Thirty-day mortality was 2/13 (one, cardiac; one, neurological) with no late deaths. The mean time from embolic stroke to surgery was 2.3 weeks (range 3-60 days). The reason for operating on eight patients in less than two weeks was heart failure in five, uncontrolled sepsis, AMI and TIA (one each). 2/8 (25%) suffered additional postoperative neurological events (one, brain death, one, new MCA stroke). On follow-up of the remaining eight patients with embolic events, five had improved neurology and three had stable neurology. The mean time to surgery from haemorrhagic stroke was 5.8 weeks (range 3-60 days). Deficit improved in two patients (<1 week, 1; >8 weeks, 1). On follow-up the NYHA class was I-II in 6/11 (56%). The EQ-5D questionnaire was used to assess quality of life. Mean index for the group was 0.67 using the US preference-weighted index score (SD 0.27). CONCLUSIONS Results regarding timing for haemorrhagic stroke cannot be defined from the small numbers. Timely surgical intervention (embolic greater than two weeks and preferably four weeks in absence of heart failure) is associated with acceptable neurological outcome, functional class and quality of life.

Contemporary results following surgical repair of acute type a aortic dissection (AAAD): a single centre experience.

OBJECTIVES The study aims to define predictors of neurological dysfunction, 30-day mortality, long-term survival and quality of life following repair of acute type A aortic dissection (AAAD). METHODS Between 2000 and 2008, 65 patients underwent repair of AAAD. Sixty-four pre-, intra- and post-operative variables were studied. Mean follow-up was 26.6 months. RESULTS The mean age was 61years; 60% were male and five had Marfans syndrome. At presentation, ischaemic ECG changes were seen in 45%, malperfusion syndrome in 59%, moderate-severe aortic regurgitation in 48% and tamponade in 16%. EF was <40% in 17%. There was a delay of >12hours between diagnosis and operation in 64%. Axillary cannulation was performed in 37%. Cerebral protection was by hypothermic arrest (HCA) alone (19%), HCA with retrograde cerebral perfusion (RCP) (11%), or HCA with antegrade cerebral perfusion (ACP) (46%). The procedure was performed on cross-clamp in 24%. Full arch replacement was performed in 14% and concomitant coronary artery grafting was performed in 11%. Post-operative neurological dysfunction was present in 33.8%. The only significant predictor of poor neurological outcome was full arch replacement (p=0.04) on univariate analysis. In-hospital OR 30 mortality was 23.53%. Significant predictors of mortality were low ejection fraction (p=0.017) and post-operative renal failure (p=0.012). Long-term survival was 70% at two years, 50% at five years and 25% at nine years. Functional outcomes and long-term quality of life were assessed in 69% of patients who were alive at last follow-up. Ninety percent of patients reported minimal limitation on functional scores. Quality of life was assessed using the EQ-5D questionnaire. Forty-eight percent of patients recorded full health with an overall mean index of 0.854 (where the best possible score is 1) using the US preference weighted index score. CONCLUSIONS Discharged patients have reasonable long-term survival and good quality of life.

Cardiac tumors in adults: surgical management and follow-up of 19 patients in an Australian tertiary hospital

The objective of this report is to share our experience with the different types of cardiac tumors, surgical management, postoperative complications and mid-term outcome of patients in an Australian tertiary hospital. Nineteen patients underwent cardiac surgery for tumors between 2001 and 2008. Their data was prospectively collected and retrospectively analyzed. The mean follow-up was 17 months. The follow-up was 100% through telephone interviews. There were multiple presenting symptoms with shortness of breath (7/19) as the most common. The tumors were atrial myxoma (14/19), fibroelastoma (2/19), angiosarcoma (1/19) and intravascular leiomyomatosis (1/19). A calcified thrombus (1/19) was misdiagnosed as a tumor. The fibroelastomas were shaved preserving valvular function. The angiosarcoma was incompletely resected with palliation intent. The leiomyomatosis and atrial myxoma were completely resected with satisfactory outcome. There was no in-hospital mortality. All patients were alive and were in New York Heart Association (NYHA) class I, except for the patient with a high-grade angiosarcoma who died eight months postoperatively. There was no evidence of recurrence in follow-up echocardiograms. Our experience and outcome is consistent with current literature. Atrial myxoma is the most common cardiac tumor and is curable with complete surgical resection. Fibroelastomas can be shaved off with low-risk of recurrence. Surgical management of angiosarcoma is palliative.

Return to work after coronary artery bypass in patients aged under 50 years

Background: This study was designed to identify factors associated with return to work and quality of life in patients undergoing primary coronary artery bypass at age <50 years. Methods: 172 patients <50-years old underwent primary coronary artery bypass between January 2000 and December 2006. Predictors of return to work were analysed from variables in a prospectively collected database and on follow-up by the SF-36 questionnaire in 129 (75%) patients. Results: 136 (79%) patients were working prior to surgery. The educational level was: primary 14.5%, secondary 47%, trade 22%, tertiary 13%, and postgraduate 3%. Type of occupation was blue collar 51%, white collar 41%, pensioner 27%, and unspecfied 8%. The mean follow-up was 86.4 ± 23.4 months. One hundred and twenty-six (69%) patients attended cardiac rehabilitation. Forty (23%) patients experienced recurrence of symptoms; 11 (6%) required reintervention. One hundred and twenty-seven (93%) patients returned to work postoperatively. Univariate predictors of return to work were male sex, blue-collar work, and working prior to surgery. Independent predictors of return to work were working prior to surgery and blue-collar work. Patients who returned to work had significantly higher scores in all 8 domains on the SF36-Questionnaire compared to those who did not return to work. Conclusions: Preoperative employment and blue collar occupation were associated with a higher rate of return to work after coronary artery bypass in patients of working age. Patients who returned to work had significantly better measured quality of life than those who did not.

Treatment outcomes for ischemic heart disease in dialysis-dependent patients

Objective: To compare outcomes following intervention in dialysis-dependent patients with ischemic heart disease. Background: Ischemic heart disease is a major cause of mortality in dialysis-dependent patients. Coronary revascularization and medical modification to relieve symptoms is common, however, there is no clear consensus regarding optimal treatment. Method: Ninety dialysis-dependent patients with ischemic heart disease were prospectively assessed between 1999 and 2009, with a median follow-up of 24 months; 35 received best medical management, 31 had percutaneous coronary angioplasty and stenting, and 24 had coronary artery bypass grafting. Results: By multivariate analysis, higher body mass index and lower logistic EuroSCORE were associated with having either procedure compared to medical management. Using the time-to-event Kaplan-Meier method, both stenting and coronary bypass grafting had lower risks of an adverse outcome than best medical management. Mortality was 40/90 (44.4%). Multivariate predictors of mortality were smoking and a logistic EuroSCORE of 7–14. Overall mortality was not different among groups, however, the stent group had a survival advantage at 30-days and 1-year compared to the coronary bypass group. Composite median survival was 52.3 months. SF-36 questionnaires showed quality of life after bypass grafting was significantly better than medical management or stenting. Physical function was better after bypass grafting compared to medical management or stenting. Conclusion: Dialysis-dependent patients with ischemic heart disease have poor survival despite intervention. Coronary artery bypass achieves fewer composite adverse events and better quality of life than stenting. Symptoms and coronary anatomy should dictate treatment decisions in dialysis-dependent patients.