David Latter

Transcatheter aortic valve implantation for the treatment of severe symptomatic aortic stenosis in patients at very high or prohibitive surgical risk: acute and late outcomes of the multicenter Canadian experience.

OBJECTIVES The aim of this study was: 1) to evaluate the acute and late outcomes of a transcatheter aortic valve implantation (TAVI) program including both the transfemoral (TF) and transapical (TA) approaches; and 2) to determine the results of TAVI in patients deemed inoperable because of either porcelain aorta or frailty. BACKGROUND Very few data exist on the results of a comprehensive TAVI program including both TA and TF approaches for the treatment of severe aortic stenosis in patients at very high or prohibitive surgical risk. METHODS Consecutive patients who underwent TAVI with the Edwards valve (Edwards Lifesciences, Inc., Irvine, California) between January 2005 and June 2009 in 6 Canadian centers were included. RESULTS A total of 345 procedures (TF: 168, TA: 177) were performed in 339 patients. The predicted surgical mortality (Society of Thoracic Surgeons risk score) was 9.8 +/- 6.4%. The procedural success rate was 93.3%, and 30-day mortality was 10.4% (TF: 9.5%, TA: 11.3%). After a median follow-up of 8 months (25th to 75th interquartile range: 3 to 14 months) the mortality rate was 22.1%. The predictors of cumulative late mortality were peri-procedural sepsis (hazard ratio [HR]: 3.49, 95% confidence interval [CI]: 1.48 to 8.28) or need for hemodynamic support (HR: 2.58, 95% CI: 1.11 to 6), pulmonary hypertension (PH) (HR: 1.88, 95% CI: 1.17 to 3), chronic kidney disease (CKD) (HR: 2.30, 95% CI: 1.38 to 3.84), and chronic obstructive pulmonary disease (COPD) (HR: 1.75, 95% CI: 1.09 to 2.83). Patients with either porcelain aorta (18%) or frailty (25%) exhibited acute outcomes similar to the rest of the study population, and porcelain aorta patients tended to have a better survival rate at 1-year follow-up. CONCLUSIONS A TAVI program including both TF and TA approaches was associated with comparable mortality as predicted by surgical risk calculators for the treatment of patients at very high or prohibitive surgical risk, including porcelain aorta and frail patients. Baseline (PH, COPD, CKD) and peri-procedural (hemodynamic support, sepsis) factors but not the approach determined worse outcomes.

Long-Term Outcomes After Transcatheter Aortic Valve Implantation Insights on Prognostic Factors and Valve Durability From the Canadian Multicenter Experience

OBJECTIVES This study sought to evaluate the long-term outcomes after transcatheter aortic valve implantation (TAVI) in the Multicenter Canadian Experience study, with special focus on the causes and predictors of late mortality and valve durability. BACKGROUND Very few data exist on the long-term outcomes associated with TAVI. METHODS This was a multicenter study including 339 patients considered to be nonoperable or at very high surgical risk (mean age: 81 ± 8 years; Society of Thoracic Surgeons score: 9.8 ± 6.4%) who underwent TAVI with a balloon-expandable Edwards valve (transfemoral: 48%, transapical: 52%). Follow-up was available in 99% of the patients, and serial echocardiographic exams were evaluated in a central echocardiography core laboratory. RESULTS At a mean follow-up of 42 ± 15 months 188 patients (55.5%) had died. The causes of late death (152 patients) were noncardiac (59.2%), cardiac (23.0%), and unknown (17.8%). The predictors of late mortality were chronic obstructive pulmonary disease (hazard ratio [HR]: 2.18, 95% confidence interval [CI]: 1.53 to 3.11), chronic kidney disease (HR: 1.08 for each decrease of 10 ml/min in estimated glomerular filtration rate, 95% CI: 1.01 to 1.19), chronic atrial fibrillation (HR: 1.44, 95% CI: 1.02 to 2.03), and frailty (HR: 1.52, 95% CI: 1.07 to 2.17). A mild nonclinically significant decrease in valve area occurred at 2-year follow-up (p < 0.01), but no further reduction in valve area was observed up to 4-year follow-up. No changes in residual aortic regurgitation and no cases of structural valve failure were observed during the follow-up period. CONCLUSIONS Approximately one-half of the patients who underwent TAVI because of a high or prohibitive surgical risk profile had died at a mean follow-up of 3.5 years. Late mortality was due to noncardiac comorbidities in more than one-half of patients. No clinically significant deterioration in valve function was observed throughout the follow-up period.

Carotid artery duplex scanning in preoperative assessment for coronary artery revascularization: The association between peripheral vascular disease, carotid artery stenosis, and stroke

PURPOSE The purpose of this study was to identify high-risk populations for severe carotid artery disease (SCD) and neurologic events (NE) after nonemergency isolated coronary artery bypass graft procedures (CABG). METHODS Between February 1989 and July 1992, 387 patients underwent preoperative carotid artery duplex scanning as part of a preoperative assessment for nonemergency cardiac procedures. Of these patients, 376 had isolated CABG, and 11 had combined carotid endarterectomy (CEA) and CABG. Patient demographics, risk factors, and preoperative neurologic symptoms were recorded and analyzed. Severe carotid artery disease was defined as a 80% or greater stenosis of either internal carotid artery by carotid artery duplex scanning. Patients were evaluated for neurologic events (cerebrovascular accident, transient ischemic attack, amaurosis fugax, or reversible ischemic neurologic deficits) during the in-hospital postoperative period. RESULTS The prevalence of SCD was 8.5% (33 patients). The 33 patients with SCD were significantly older (65.6 +/- 6.5 years vs 62.5 +/- 10.4 years, p = 0.02), had previous CEA (27.3% vs 2.0%, p = 0.00001), had preoperative neurologic symptoms (21.2% vs 5.9%, p = 0.002), and had peripheral vascular disease (PVD) (63.6% vs 16.9%, p = 0.00001). The sensitivity of PVD for SCD is 63.6% (n = 21/33) (specificity 83.1%, positive predictive value 25.9%, negative predictive value 96.1%). In patients undergoing CABG alone, those who had postoperative NE were older (69.6 +/- 6.7 years vs 62.5 +/- 10.3 years, p = 0.036) and more likely to have PVD (50% vs 19.7%, p = 0.034), SCD (40% vs 4.9%, p = 0.001) and previous CEA (40% vs 2.7%, p = 0.0002). The incidence of postoperative NE in patients with SCD was 18.2% vs 1.7% in patients without SCD (p = 0.001). The sensitivity of SCD for NE was 40% (n = 4/10) (specificity 95.1%, positive predictive value 18.2%, negative predictive value 98.3%). CONCLUSIONS PVD may be helpful to identify patients at high risk for severe carotid artery stenosis. Postoperative NE in patients with CABG are associated with increasing age, carotid artery stenosis greater than 80%, previous CEA, and PVD.

Use of "BioGlue" in aortic surgical repair.

A new bioadhesive (BioGlue, Cryolife Inc, Kennesaw, GA) was recently introduced for surgical use in thoracic aortic surgical repair. We describe our early experience and our suggested method of repair.

Should Radial Arteries Be Used Routinely for Coronary Artery Bypass Grafting

Case Presentation : Mr P is a 57-year-old construction worker who has had Canadian Cardiovascular Society class III angina for the past 3 months. He has multiple cardiovascular risk factors including smoking, hypertension, dyslipidemia, and diabetes. He is obese and has had a previous laparotomy for a perforated bowel. Coronary angiography revealed triple vessel disease involving the left anterior descending artery (LAD), the first obtuse marginal branch, and the right coronary artery (RCA), and an akinetic inferior wall with an estimated ejection fraction of 40%. The patient was referred for consideration of coronary artery bypass graft (CABG) surgery. Is Mr P a candidate for CABG and, if so, which vascular conduits should be used? CABG is the standard surgical procedure for the treatment of advanced coronary artery disease. Since the first successful results reported by Favaloro,1 CABG surgery has been demonstrated to improve symptoms and, in specific subgroups of patients, to prolong life.2 Despite its success, the long-term outcome of coronary bypass surgery is strongly influenced by the fate of the vascular conduits used. Five to 7 years after surgery, patients are at increased risk of suffering from ischemic complications coincident with graft failure.2 Furthermore, as patients undergoing CABG surgery become older with more preoperative risk factors, and treated patients are living longer and therefore requiring reoperation, the optimal selection of vascular grafts for bypass is essential. Conventional CABG surgery utilizes a combination of arterial and venous grafts. Saphenous vein (SV) grafts, the first vascular conduits used in CABG, are still widely utilized, primarily to bypass vessels other than the LAD. Despite being readily accessible, of adequate length to access every vessel on the heart, and the correct diameter to facilitate coronary and aortic anastomoses, SV grafts are limited by poor long-term patency. Because of a combination …

Can local application of Tranexamic acid reduce post-coronary bypass surgery blood loss? A randomized controlled trial

BackgroundDiffuse microvascular bleeding remains a common problem after cardiac procedures.Systemic use of antifibrinolytic reduces the postoperative blood loss.The purpose of this study was to examine the effectiveness of local application of tranexamic acid to reduce blood loss after coronary artery bypass grafting (CABG).MethodsThirty eight patients scheduled for primary isolated coronary artery bypass grafting were included in this double blind, prospective, randomized, placebo controlled study.Tranexamic acid (TA) group (19 patients) received 1 gram of TA diluted in 100 ml normal saline. Placebo group (19 patients) received 100 ml of normal saline only. The solution was purred in the pericardial and mediastinal cavities.ResultsBoth groups were comparable in their baseline demographic and surgical characteristics. During the first 24 hours post-operatively, cumulative blood loss was significantly less in TA group (median of 626 ml) compared to Placebo group (median of 1040 ml) (P = 0.04). There was no significant difference in the post-op Packed RBCs transfusion between both groups (median of one unit in each) (P = 0.82). Significant less platelets transfusion required in TA group (median zero unit) than in placebo group (median 2 units) (P = 0.03). Apart from re-exploration for excessive surgical bleeding in one patient in TA group, no difference was found in morbidity or mortality between both groups.ConclusionTopical application of tranexamic acid in patients undergoing primary coronary artery bypass grafting led to a significant reduction in postoperative blood loss without adding extra risk to the patient.

Successful treatment using recombinant factor VIIa for severe bleeding post cardiopulmonary bypass

PurposeTo describe a case of persistent and excessive bleeding following an aortic valve and ascending aorta replacement that was successfully managed with recombinant factor VIIa (rFVIIa). The postulated mechanisms for rFVIIa are discussed.Clinical featuresA 75-yr-old female with no preoperative coagulopathy underwent a tissue aortic valve replacement and supracoronary ascending aorta replacement for severe aortic stenosis and an ascending aortic aneurysm. Following surgery, she bled in excess of 200 mL·hr−1 despite a nearly normal platelet count and nearly normal coagulation parameters. The patient was surgically re-explored twice in seven hours, and despite the presence of near normalin vitro coagulation parameters, the patient continued to bleed. Multiple units of fresh frozen plasma, platelets and cryoprecipitate were administered empirically. We then administered a single 6-mg (107 μg·kg−1)iv dose of rFVIIa. Following the administration of rFVIIa, blood loss decreased to a total of 440 mL over the next 12 hr.ConclusionsThis case describes the use of rFVIIa for intractable bleeding postcardiovascular surgery in the presence of nearly normal laboratory markers of coagulation. Further controlled laboratory and clinical studies are required to define the role of rFVIIa in patients undergoing cardiovascular surgery.RésuméObjectifDécrire un cas de saignement persistant et abondant, après le remplacement d’une valvule aortique et de l’aorte ascendante, traité avec succès par le facteur VIIa recombinant (rFVIIa). Les mécanismes proposés pour le rFVIIa sont discutés.Éléments cliniquesUne femme de 75 ans, sans coagulopathie préopératoire, a subi le remplacement tissulaire d’une valve aortique et le remplacement de l’aorte ascendante supracoronaire à cause d’une sténose aortique sévère et d’un anévrysme de l’aorte ascendante. Après l’opération, elle a perdu beaucoup de sang, plus de 200 mL·hr−1 malgré une numération plaquettaire normale et des paramètres de coagulation près de la normale. La patiente a été réopérée, deux fois en sept heures et, malgré des paramètres de coagulation in vitro pratiquement normaux, a continué à saigner. De nombreuses unités de plasma frais congelé, de plaquettes et de cryoprécipités ont été administrées empiriquement. Nous avons donné ensuite une seule dose iv de 6 mg (107 μg·kg−1) de rFVIIa. Après quoi l’hémorragie a diminué à 440 mL pendant les 12 h suivantes.ConclusionCe cas illustre l’usage du rFVIIa pour traiter des saignements réfractaires après une opération cardiovasculaire en présence de marqueurs de coagulation pratiquement normaux. D’autres études cliniques contrôlées et d’autres études de laboratoire contrôlées sont nécessaires à la définition du rôle du rFVIIa chez des patients en chirurgie cardiovasculaire.

Determinants of variations in coronary revascularization practices

Background: The ratio of percutaneous coronary interventions to coronary artery bypass graft surgeries (PCI:CABG ratio) varies considerably across hospitals. We conducted a comprehensive study to identify clinical and nonclinical factors associated with variations in the ratio across 17 cardiac centres in the province of Ontario. Methods: In this retrospective cohort study, we selected a population-based sample of 8972 patients who underwent an index cardiac catheterization between April 2006 and March 2007 at any of 17 hospitals that perform invasive cardiac procedures in the province. We classified the hospitals into four groups by PCI:CABG ratio (low [< 2.0], low–medium [2.0–2.7], medium–high [2.8–3.2] and high [> 3.2]). We explored the relative contribution of patient, physician and hospital factors to variations in the likelihood of patients receiving PCI or CABG surgery within 90 days after the index catheterization. Results: The mean PCI:CABG ratio was 2.7 overall. We observed a threefold variation in the ratios across the four hospital ratio groups, from a mean of 1.6 in the lowest ratio group to a mean of 4.6 in the highest ratio group. Patients with single-vessel disease usually received PCI (88.4%–99.0%) and those with left main artery disease usually underwent CABG (80.8%–94.2%), regardless of the hospital’s procedure ratio. Variation in the management of patients with non-emergent multivessel disease accounted for most of the variation in the ratios across hospitals. The mode of revascularization largely reflected the recommendation of the physician performing the diagnostic catheterization and was also influenced by the revascularization “culture” at the treating hospital. Interpretation: The physician performing the diagnostic catheterization and the treating hospital were strong independent predictors of the mode of revascularization. Opportunities exist to improve transparency and consistency around the decision-making process for coronary revascularization, most notably among patients with non-emergent multivessel disease.

Growth factor-induced therapeutic neovascularization for ischaemic vascular disease: time for a re-evaluation?

Purpose of review Therapeutic angiogenesis and arteriogenesis represent an alternative treatment modality for patients with advanced ischaemic coronary or peripheral artery occlusive disease, who are unsuitable for standard revascularization procedures. Recent developments Proof-of-concept evidence for therapeutic growth factor, both gene and protein-mediated neovascularization was provided in animal models of chronic myocardial and hindlimb ischaemia. Early human, phase I, trials utilizing the prototypical growth factor families, vascular endothelial growth factor and fibroblast growth factor, documented safety and suggested improvements in anginal symptoms and functional status. Large, randomized, placebo-controlled phase II/III clinical trials have, however, yielded variable results as such studies have suffered from significant limitations in therapeutic approach or design, which limits the ability to draw firm conclusions. Summary Future trials must incorporate robust delivery strategies and address issues of study design including proper patient selection. Laboratory-based refinements in therapy, including a focus on the promotion of arteriogenesis and the modification of patient ‘endotheliopathy’, will all further enhance the potential of therapeutic neovascularization strategies.

Off-Pump Coronary Artery Bypass Surgery Fundamentals for the Clinical Cardiologist

Case Report: Mrs. G is a 65-year-old retired banker who has had Canadian Cardiovascular Society class III angina for the past 2 months and symptomatic intermittent claudication for the past year. Her past medical history is unremarkable except for the presence of multiple vascular risk factors (smoking, hypertension, dyslipidemia, and diabetes). Coronary angiography revealed triple vessel disease involving the left anterior descending, second obtuse marginal, and right coronary arteries, as well as the akinetic anterior and inferior walls, with an estimated ejection fraction of 30%. Carotid duplex revealed 40% stenosis of the right internal carotid artery and 60% stenosis of the left internal carotid artery. A chest x-ray showed a possible calcified ascending aorta. The patient was referred for consideration of coronary artery bypass graft (CABG) surgery. Is Mrs. G a candidate for off-pump CABG? What are the indications, precautions, and considerations that facilitate decision-making about off-pump CABG surgery? Conventional CABG surgery uses cardiopulmonary bypass (CPB) to allow cardiac surgeons to operate on a motionless heart that has been arrested by means of cardioplegia. CABG with CPB (on-pump CABG) quickly became the gold standard surgical procedure for myocardial revascularization, as it allowed surgeons to bypass multiple coronary arteries with greater control and precision. However, recently there has been increasing interest in the development and use of technologies that allow surgeons to perform CABG surgery without CPB (known as off-pump CABG or OPCAB). CPB is not a benign intervention. It is associated with a number of adverse consequences that are primarily related to a systemic inflammatory response elicited by the activation of cellular and humoral mediators as circulating blood comes into contact with the extracorporeal circuit of the CPB machine. The biochemical, cellular, and molecular aspects of this pump-induced inflammatory response are believed to contribute to postoperative myocardial, renal, and neurological …