P. Garrahy

Validation of a Generalized Transfer Function to Noninvasively Derive Central Blood Pressure During Exercise

Exercise brachial blood pressure (BP) predicts mortality, but because of wave reflection, central (ascending aortic) pressure differs from brachial pressure. Exercise central BP may be clinically important, and a noninvasive means to derive it would be useful. The purpose of this study was to test the validity of a noninvasive technique to derive exercise central BP. Ascending aortic pressure waveforms were recorded using a micromanometer-tipped 6F Millar catheter in 30 patients (56±9 years; 21 men) undergoing diagnostic coronary angiography. Simultaneous recordings of the derived central pressure waveform were acquired using servocontrolled radial tonometry at rest and during supine cycling. Pulse wave analysis of the direct and derived pressure signals was performed offline (SphygmoCor 7.01). From rest to exercise, mean arterial pressure and heart rate were increased by 20±10 mm Hg and 15±7 bpm, respectively, and central systolic BP ranged from 77 to 229 mm Hg. There was good agreement and high correlation between invasive and noninvasive techniques with a mean difference (±SD) for central systolic BP of −1.3±3.2 mm Hg at rest and −4.7±3.3 mm Hg at peak exercise (for both r=0.995; P<0.001). Conversely, systolic BP was significantly higher peripherally than centrally at rest (155±33 versus 138±32 mm Hg; mean difference, −16.3±9.4 mm Hg) and during exercise (180±34 versus 164±33 mm Hg; mean difference, −15.5±10.4 mm Hg; for both P<0.001). True myocardial afterload is not reliably estimated by peripheral systolic BP. Radial tonometry and pulse wave analysis is an accurate technique for the noninvasive determination of central BP at rest and during exercise.

Increased platelet-derived microparticles in the coronary circulation of percutaneous transluminal coronary angioplasty patients

Platelet-derived microparticles that are produced during platelet activation are capable of adhesion and aggregation. Endothelial trauma that occurs during percutaneous transluminal coronary angioplasty (PTCA) may support platelet-derived microparticle adhesion and contribute to development of restenosis. We have previously reported an increase in platelet-derived microparticles in peripheral arterial blood with angioplasty. This finding raised concerns regarding the role of platelet-derived microparticles in restenosis, and therefore the aim of this study was to monitor levels in the coronary circulation. The study population consisted of 19 angioplasty patients. Paired coronary artery and sinus samples were obtained following heparinization, following contrast administration, and subsequent to all vessel manipulation. Platelet-derived microparticles were identified with an anti-CD61 (glycoprotein IIIa) fluorescence-conjugated antibody using flow cytometry. There was a significant decrease in arterial platelet-derived microparticles from heparinization to contrast administration (P = 0.001), followed by a significant increase to the end of angioplasty (P = 0.004). However, there was no significant change throughout the venous samples. These results indicate that the higher level of platelet-derived microparticles after angioplasty in arterial blood remained in the coronary circulation. Interestingly, levels of thrombin–antithrombin complexes did not rise during PTCA. This may have implications for the development of coronary restenosis post-PTCA, although this remains to be determined.

Angiographic follow‐up and clinical experience with the flexible tantalum cordis stent

The Cordis stent is a flexible, highly radioopaque intracoronary stent engineered from a single Tantalum filament folded into a sinusoidal helical coil. It is premounted on a semicompliant balloon expandable stent delivery system. From September 1995-March 1996, 147 Cordis stents were deployed in 105 patients (aged 58+/-12 yr, 71% male). Clinical indications for stenting were unstable angina in 59 (55%), stable angina in 41 (38%), and acute myocardial infarction in 7 (7%). The target vessel was the right coronary artery in 45%, the left anterior descending in 31%, and the circumflex artery in 22%. One stent was deployed in a vein graft, and one stent was deployed in a left internal mammary artery graft. Stent deployment was achieved in all but one patient. Acute in-stent thrombosis occurred in 3 patients (2.9%). Two of these patients required urgent coronary artery bypass surgery. Subacute stent thrombosis occurred in 2 patients (1.9%). Minimum lumen diameter increased from 0.70+/-0.41 mm to 3.50+/-0.60 mm following stent placement. All patients received aspirin. Eighty-one patients (77%) received ticlopidine, and 4 patients (4%) received warfarin therapy. The mean hospital stay was 3.4+/-2.3 days. Six-month follow-up angiography was performed on 50 out of 55 eligible patients at one of the two institutions involved in this study. Computer-assisted quantitative coronary angiography defined a restenosis rate of 26%. Repeat revascularization was required in 8 patients (14.5%) at 6-mo follow-up. The Tantalum Cordis intracoronary stent is an effective and safe means of treating coronary lesions, even in patients with unstable ischemic syndromes. Acute and subacute rates of in-stent thrombosis were acceptable, and the long-term angiographic restenosis rates and need for repeat revascularization were favorable.

Transcatheter aortic valve replacement is associated with comparable clinical outcomes to open aortic valve surgery but with a reduced length of in-patient hospital stay: a systematic review and meta-analysis of randomised trials

BACKGROUND Aortic valve replacement is indicated in patients with severe symptomatic aortic stenosis (AS). Transcatheter aortic valve replacement (TAVR) has evolved as a potential strategy in a growing proportion of patients in preference to surgical aortic valve replacement (SAVR). This meta-analysis aims to assess the differential outcomes of TAVR and SAVR in patients enrolled in published randomised controlled trials (RCTs). METHODS A systematic literature search of Cochrane Library, EMBASE, OVID, and PubMed MEDLINE was performed. Randomised controlled trials of patients with severe AS undergoing TAVR compared with SAVR were included. Clinical outcomes and procedural complications were assessed. RESULTS Five RCTs with a total of 3,828 patients (1,928 TAVR and 1,900 SAVR) were analysed. There was no statistically significant difference in combined rates of all-cause mortality and stroke at 30-days for TAVR vs SAVR (6.3% vs 7.5%; OR 0.83; 95% CI: 0.64-1.08; P=0.17) or at 12 months (17.2% vs 19.2%; OR 0.87; 95% CI: 0.73-1.03; P=0.29). No statistically significant difference was seen for death or stroke separately at any time point although a numerical trend in favour of TAVR for both was recorded. Length of in-patient stay was significantly less with TAVR vs SAVR (9.6 +/- 7.7 days vs 12.2 +/- 8.8 days; OR -2.94; 95% CI: -4.64 to -1.24; P=0.0007). Major vascular complications were more frequent in patients undergoing TAVR vs SAVR (8.2% vs. 4.0%; OR 2.15; 95% CI: 1.62-2.86; P <0.00001) but major bleeding was more common among SAVR patients (20.5% vs 44.2%; OR 0.34; 95% CI: 0.22-0.52; P=<0.00001). CONCLUSIONS Transcatheter aortic valve replacement and SAVR are associated with overall similar rates of death and stroke among patients in intermediate to high-risk cohorts but with reduced length of in-patient hospital stay.

Stress-induced takotsubo cardiomyopathy in survivors of the 2011 Queensland floods.

The Medical Journal of Australia ISSN: 0025729X 4 February 2013 198 2 109-110 ©The Medical Journal of Australia 2013 www.mja.com.au Notable Cases showed sinus rhythm and normal ca and QRS duration. There was T-wave III, aVF and V3–V6. The patient’s seru elevated to 1.3g/L (reference inter Results of biochemistry and haematol erwise unremarkable. Her respiratory signs improved qui We report the first two Australian cases of flood-related takotsubo cardiomyopathy, in patients who were trapped by life-threatening flash floods in and near Toowoomba, Queensland. It is well recognised that events that incite significant physical and emotional stress in individuals can trigger this syndrome, which often mimics acute myocardial infarction.

Baseline and residual SYNTAX score in predicting outcomes after acute infarct angioplasty

AIMS The aim of this study was to explore the utility of baseline SYNTAX score (bSS) and residual SYNTAX score (rSS) in predicting 12-month outcomes after primary percutaneous coronary intervention (PPCI). METHODS AND RESULTS Five hundred and ninety all-comers with acute STEMI presenting for PPCI over a two-year period were identified. Of these, 173 were excluded because of unsuitability for SYNTAX score calculation for this study. Two experienced observers calculated the bSS and rSS. Mortality data were sourced from the government registry. Logistic regression was used to assess the predictive power of bSS and rSS for mortality. Sensitivity analysis and a Cox proportional hazards model were used to evaluate the best cut-off for increased mortality. Of the 417 patients analysed (mean age 59 years), 81% were male and 18% were known diabetics. At 12 months, the overall mortality rate was 5.5% (23/417). An rSS of >12 was associated with a 13.95% mortality rate. The hazard ratio for mortality was 3.88 (95% CI: 1.49-10.09, p=0.005) for rSS of >12 and 3.01 (95% CI: 1.18-7.64, p=0.02) for bSS >12. The odds ratio (OR) for mortality was 1.06 (95% CI: 1.02-1.11, p=0.009) for rSS and 1.05 (95% CI: 1.02-1.1, p=0.007) for bSS. CONCLUSIONS In STEMI patients undergoing PPCI, both bSS and rSS can predict mortality at 12 months. Every point on the rSS confers an additional 6% mortality risk. Calculation of the rSS after culprit lesion intervention may help guide management of non-culprit lesions.

Surgical pulmonary embolectomy: mid-term outcomes

Despite the widespread use of venous thromboembolism (VTE) prophylaxis in hospitalized patients, pulmonary embolism continues to occur. Massive pulmonary embolism is associated with a high mortality. Surgical embolectomy has traditionally been reserved for cases with haemodynamic collapse or where thrombolysis is contraindicated or has failed.

Drug Eluting Stents Versus Coronary Artery Bypass Grafts for Left Main Coronary Disease: A Meta-Analysis and Review Of Randomised Controlled Trials

BACKGROUND Revascularisation of left main coronary artery (LMCA) disease can be potentially managed with percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). Recent randomised controlled trial (RCT) data have added to the literature on this subject and this meta-analysis aims to assess the state of the data to assist in guiding patient treatment decisions. METHODS A systematic literature search of Cochrane Library, EMBASE, OVID, and PubMed Medline was performed. Randomised controlled trials of patients with LMCA disease undergoing PCI with drug eluting stents or CABG were included. Clinical outcomes and adverse events were assessed and analysed. RESULTS Four suitable RCTs of adequate quality and follow-up were identified. The incidence of major adverse cardiac and cerebrovascular events (MACCE) at 3 to 5 years of follow-up was significantly increased with PCI compared to CABG (23.3% vs 18.2%, OR 1.37; 95% CI: 1.18-1.58; p=<0.0001; I2=0%) and was largely driven by more repeat revascularisation procedures among patients treated with PCI. There was no statistically significant difference in rates of mortality, myocardial infarction or stroke (either individually or when these outcomes were combined as a composite endpoint). CONCLUSIONS Coronary artery bypass grafting and PCI both represent reasonable treatment modalities for LMCA disease in appropriately selected patients. However, where CABG is feasible it offers superior long-term freedom from repeat revascularisation. Longer-term follow-up is required to further clarify the durability of mortality outcomes, especially in patients treated with PCI.

Can myocardial contrast echo provide incremental benefit to exercise echo? Implications of the intensity and duration of hyperaemia

Background. Although the evidence for applying specialist nurse-led programs of care to optimise the postdischarge management of chronic heart failure (CHF) is compelling, the majority of randomised studies have either applied a clinic or home-based approach. In practice, however, many programs employ a pragmatic combination of the two.