Farzin Fath-Ordoubadi

A meta‐analysis of the prognostic significance of atrial fibrillation in chronic heart failure

Atrial fibrillation (AF) is one of the commonest sustained arrhythmias in chronic heart failure (CHF), although the prognostic implications of the presence of AF in CHF remain controversial. We have therefore performed this meta‐analysis to study the effects of the presence of AF on mortality in CHF patients.

Influence of access site selection on PCI-related adverse events in patients with STEMI: meta-analysis of randomised controlled trials

Objective A meta-analysis of all randomised controlled studies that compare outcomes of transradial versus the transfemoral route to better define best practice in patients with ST elevation myocardial infarction (STEMI). Design A Medline and Embase search was conducted using the search terms ‘transradial,’ ‘radial’, ‘STEMI’, ‘myocardial’ and ‘infarction’. Setting Randomised controlled studies that compare outcomes of transradial versus the transfemoral route. Patients A total of nine studies were identified that consisted of 2977 patients with STEMI. Interventions Studies that compare outcomes of transradial versus the transfemoral route. Main outcome measures The primary clinical outcomes of interest were (1) mortality; (2) major adverse cardiac events (MACE); (3) major bleeding and (4) access site complications. Results Transradial PCI was associated with a reduction in mortality (OR 0.53, 95% CI 0.33 to 0.84; p=0.008), MACE (OR 0.62, 95% CI 0.43 to 0.90; p=0.012), major bleeding events (OR 0.63, 95% CI 0.35-1.12; p=0.12) and access site complications (OR 0.30, 95% CI 0.19 to 0.48; p<0.0001) compared with procedures performed through the femoral route. Conclusions This meta-analysis demonstrates a significant reduction in mortality, MACE and major access site complications associated with the transradial access site in STEMI. The meta-analysis supports the preferential use of radial access for STEMI PCI.

Longitudinal stent deformation: a retrospective analysis of frequency and mechanisms.

AIMS Modern drug-eluting stents are constructed with thin struts and are easy to deliver and highly conformable. However, although innovative designs have enabled maintenance of radial strength, longitudinal strength may be lower with these stents and there have been recent reports of longitudinal stent compression of ostially deployed stents. We report the experience in our centre on longitudinal stent deformation and explore mechanisms of this complication and its frequency with various drug-eluting stent platforms. METHODS AND RESULTS Nine cases of longitudinal stent deformation were identified over a four year period representing 0.2% of cases and affected 0.097% of stents deployed. There were several mechanisms for this complication including compression by post-dilatation balloons, guide catheter extensions and proximal embolic protection devices. The rate of stent deformation varied from 0% in several stent types to 0.86% in the case of the Promus Element stent. There was one case of late stent thrombosis attributable to longitudinal stent deformation. CONCLUSIONS Longitudinal stent deformation can occur secondary to a variety of mechanisms and identification is important as, left untreated, it may be associated with a risk of stent thrombosis. Although seen with several different stents, in our series it was more commonly observed with the Promus Element stent.

Measurement of myocardial blood flow with oxygen-15 labelled water: comparison of different administration protocols

Abstract Positron emission tomography (PET) in conjunction with C15O2 or H215O can be used to measure myocardial blood flow (MBF) and tissue fraction (TF), i.e. the fraction of the tissue mass in the volume of the region of interest. However, with C15O2 inhalation, the tissue fraction in the septum is overestimated. Bolus injection of H215O together with arterial cannulation gives very precise results but is invasive. The purpose of this study was to develop a method which circumvents these problems. A four-parameter model with parameters for MBF, TF and spill-over fractions from both left and right ventricular cavities was developed. This method was compared with a three-parameter model (no right ventricular cavity spill-over) in both septal and non-septal regions of interest for three different administration protocols: bolus injection of H215O, infusion of H215O and inhalation of C15O2. It was found that MBF can be measured with intravenous administration of H215O without the requirement for arterial cannulation. The four-parameter protocol with bolus injection was stable in clinical studies. The four-parameter model proved essential for the septum, where it gave highly significantly better fits than did the three-parameter model (P<0.00003 in each of 15 subjects). Administration of H215O together with this four-parameter model also circumvented the problem of overestimation of TF in the septum seen with C15O2 inhalation. In addition, the radiation dose of H215O protocols is lower than that of C15O2 inhalation. Using a left atrial input curve instead of a left ventricular cavity input curve gave the same mean MBF and TF.

Use of the sheathless guide catheter during routine transradial percutaneous coronary intervention: a feasibility study.

Objective: The aim of this study is to investigate the feasibility of using a 6.5 Fr sheathless guide catheter as a default system in transradial (TRA) percutaneous coronary intervention (PCI). Background: TRA PCI has been shown to reduce mortality rates through a reduction in access site related bleeding complications compared with procedures performed though a femoral approach. Complications associated with the TRA route increase with the size of sheath used. These complications may be reduced by the use of a sheathless guide catheter system (Asahi Intecc, Japan) that is 1–2 Fr sizes smaller in diameter than the corresponding introducer sheath. Methods: We performed PCI in 100 consecutive cases using 6.5 Fr sheathless guides to determine the procedural success, rates of symptomatic radial spasm and radial occlusion. Results: Procedural success using the 6.5 Fr sheathless guide catheter system was 100% with no cases requiring conversion to a conventional guide and catheter system. There were no procedural complications recorded associated with the use of the catheter. Adjunctive devices used in this cohort included IVUS, stent delivery catheters, distal protection devices, and simple thrombectomy catheters. The rate of radial spasm was 5% and the rate of radial occlusion at 2 months was 2%. Conclusion: Use of the 6.5 Fr sheathless guide catheter system, which has an outer diameter <5 Fr sheath, as the default system in routine PCI is feasible with a high rate of procedural success via the radial artery.

Distal Stent Delivery With Guideliner Catheter: First in Man Experience

Failure to deliver stents is one of the commonest causes of procedural failure in contemporary PCI practice. We describe successful use of the Guideliner Catheter, the first purpose designed FDA and CE marked device delivery catheter in 13 complex cases in native coronary vessels and bypass grafts performed via the radial route to enable distal stent delivery following failure of conventional techniques. We discuss how the Guideliner catheter may be used to facilitate difficult radial cases.

Activation of Pak1/Akt/eNOS signaling following sphingosine-1-phosphate release as part of a mechanism protecting cardiomyocytes against ischemic cell injury.

We investigated whether plasma long-chain sphingoid base (LCSB) concentrations are altered by transient cardiac ischemia during percutaneous coronary intervention (PCI) in humans and examined the signaling through the sphingosine-1-phosphate (S1P) cascade as a mechanism underlying the S1P cardioprotective effect in cardiac myocytes. Venous samples were collected from either the coronary sinus (n = 7) or femoral vein (n = 24) of 31 patients at 1 and 5 min and 12 h, following induction of transient myocardial ischemia during elective PCI. Coronary sinus levels of LCSB were increased by 1,072% at 1 min and 941% at 5 min (n = 7), while peripheral blood levels of LCSB were increased by 579% at 1 min, 617% at 5 min, and 436% at 12 h (n = 24). In cultured cardiac myocytes, S1P, sphingosine (SPH), and FTY720, a sphingolipid drug candidate, showed protective effects against CoCl induced hypoxia/ischemic cell injury by reducing lactate dehydrogenase activity. Twenty-five nanomolars of FTY720 significantly increased phospho-Pak1 and phospho-Akt levels by 56 and 65.6% in cells treated with this drug for 15 min. Further experiments demonstrated that FTY720 triggered nitric oxide release from cardiac myocytes is through pertussis toxin-sensitive phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase signaling. In ex vivo hearts, ischemic preconditioning was cardioprotective in wild-type control mice (Pak1f/f), but this protection appeared to be ineffective in cardiomyocyte-specific Pak1 knockout (Pak1cko) hearts. The present study provides the first direct evidence of the behavior of plasma sphingolipids following transient cardiac ischemia with dramatic and early increases in LCSB in humans. We also demonstrated that S1P, SPH, and FTY720 have protective effects against hypoxic/ischemic cell injury, likely a Pak1/Akt1 signaling cascade and nitric oxide release. Further study on a mouse model of cardiac specific deletion of Pak1 demonstrates a crucial role of Pak1 in cardiac protection against ischemia/reperfusion injury.

Atraumatic complex transradial intervention using large bore sheathless guide catheter.

The Asahi sheathless guide catheter system is a hydrophilic catheter with a central dilator that does not require an introducer sheath during transradial percutaneous coronary intervention. Conventional sheath introducers are often 1- to 2F larger than the catheter itself; therefore, this system enables the use of a larger French catheter during procedures than would otherwise be possible using conventional techniques. We describe the use of a 7.5F sheathless guide catheter system with a smaller outer diameter than a conventional 6F introducer sheath in 16 cases performed transradially involving rotablation, crush stent bifurcation lesions, 7F proximal protection, and thrombectomy devices. Such cases would otherwise not always be possible if performed using conventional transradial techniques in patients with smaller radial artery sizes.

Efficacy of coronary angioplasty for the treatment of hibernating myocardium

OBJECTIVES To determine the efficacy of coronary angioplasty as the sole method of revascularisation in patients with coronary artery disease and chronically dysfunctional but viable myocardium (hibernating myocardium), and to assess the effect of restenosis on functional outcome. DESIGN AND PATIENTS 24 consecutive patients with hibernating myocardium were studied. Positron emission tomography was used to assess myocardial viability, blood flow, and flow reserve. One patient refused angioplasty, one had bypass surgery, and one died while waiting for an elective procedure. The procedure failed in three patients. The remaining 18 patients had repeat echocardiography, 15 had repeat coronary angiography, and nine had repeat assessments of blood flow and flow reserve at mean (SD) 17 (2) weeks after angioplasty. In three patients restenosis was documented. RESULTS The wall motion score index in the revascularised territories improved from 1.71 (0.37) to 1.34 (0.47) (p = 0.008). Thirty of 51 dysfunctional segments improved in territories without restenosis compared with three of 14 in restenosed territories (p = 0.001). Hibernating and normal segments had comparable flows (0.82 (0.26) v0.89 (0.24) ml/min/g; NS) while flow reserve was lower in hibernating segments (1.55 (0.68) v 2.07 (1.08); p = 0.03). In segments without restenosis flow reserve improved from 2.03 (1.25) to 2.33 (1.4) (p = 0.03). Sensitivity, specificity, and positive and negative predictive accuracy of the viability study were 97%, 77%, 82%, and 96%, respectively. After excluding patients with restenosis, specificity and positive predictive accuracy improved to 90% and 93%. CONCLUSIONS Angioplasty improves function in hibernating myocardium, and restenosis prevents recovery; hibernating myocardium is characterised by an impairment of flow reserve; restenosis affects the diagnostic accuracy of viability studies.

Effects of coronary revascularisation on myocardial blood flow and coronary vasodilator reserve in hibernating myocardium

OBJECTIVE Previous studies have suggested that resting myocardial blood flow is within normal limits in most chronically dysfunctional left ventricular segments which improve function after coronary artery revascularisation (hibernating myocardium). The aim of this study was to assess myocardial blood flow and coronary vasodilator reserve in hibernating myocardium before and after coronary revascularisation. PATIENTS AND METHODS 30 patients with multivessel coronary disease undergoing coronary revascularisation (21 patients with bypass grafting and nine with coronary angioplasty), and 21 age and sex matched healthy volunteers (controls). Myocardial blood flow (MBF, ml/min/g) was measured by positron emission tomography using oxygen-15 water at rest and after dipyridamole (MBFdip, 0.56 mg/kg in four minutes). Coronary vasodilator reserve was calculated as MBFdip/MBF. Regional wall motion was assessed with echocardiography. RESULTS Before revascularisation there were 48 remote and 275 dysfunctional myocardial segments, of which 163 (59%) improved function after revascularisation (hibernating). In hibernating segments coronary vasodilator reserve before revascularisation was significantly lower than in remote segments (1.97 (0.7), p < 0.0001) and controls (3.2 (1.5), p < 0.0001). In hibernating segments, myocardial blood flow remained unchanged after revascularisation (0.94 (0.3)v 0.95 (0.3) ml/min/g, p = 0.3) while coronary vasodilator reserve increased (1.47 (0.7)v 1.98 (1.0), p < 0.0001). Myocardial blood flow was similar in remote, hibernating segments before and after revascularisation and in controls. CONCLUSIONS This study confirms that myocardial blood flow at rest in hibernating myocardium is within normal limits in most segments, and that hibernating myocardium is characterised by an impaired coronary vasodilator reserve which improves significantly after coronary revascularisation.