Guy Berkenboom

Guidelines for pre-operative cardiac risk assessment and perioperative cardiac management in non-cardiac surgery

The American College of Cardiology, American Heart Association, and the European Society of Cardiology are all in the process of completing updated versions of our Guidelines for Perioperative Care. Our respective writing committees are undertaking a careful analysis of all relevant validated studies and always incorporate appropriate new trials and meta-analyses into our evidence review. In the interim, our current joint position is that the initiation of beta blockers in patients who will undergo non-cardiac surgery should not be considered routine, but should be considered carefully by each patients treating physician on a case-by-case basis. Please see the expression of concern which is free to view in Eur Heart J (2013) 34 (44): 3460; doi: 10.1093/eurheartj/eht431. AAA : abdominal aortic aneurysm ACC : American College of Cardiology ACE : angiotensin-converting enzyme ACS : acute coronary syndrome AHA : American Heart Association AR : aortic regurgitation ARB : angiotensin receptor blocker AS : aortic stenosis AF : atrial fibrillation BBSA : β-blocker in spinal anaesthesia BNP : brain natriuretic peptide CABG : coronary artery bypass grafting CARP : coronary artery revascularization prophylaxis CASS : coronary artery surgery study CI : confidence interval COX-2 : cyclooxygenase-2 COPD : chronic obstructive pulmonary disease CPET : cardiopulmonary exercise testing CPG : Committee for Practice Guidelines CRP : C-reactive protein CT : computed tomography cTnI : cardiac troponin I cTnT : cardiac troponin T CVD : cardiovascular disease DECREASE : Dutch Echocardiographic Cardiac Risk Evaluating Applying Stress Echo DES : drug-eluting stent DIPOM : Diabetes Postoperative Mortality and Morbidity DSE : dobutamine stress echocardiography ECG : electrocardiography ESC : European Society of Cardiology FEV1 : forced expiratory volume in 1 s FRISC : fast revascularization in instability in coronary disease HR : hazard ratio ICU : intensive care unit IHD : ischaemic heart disease INR : international normalized ratio LMWH : low molecular weight heparin LQTS : long QT syndrome LR : likelihood ratio LV : left ventricular MaVS : metoprolol after surgery MET : metabolic equivalent MI : myocardial infarction MR : mitral regurgitation MRI : magnetic resonance imaging MS : mitral stenosis NICE-SUGAR : normoglycaemia in intensive care evaluation and survival using glucose algorithm regulation NSTEMI : non-ST-segment elevation myocardial infarction NT-proBNP : N-terminal pro-brain natriuretic peptide NYHA : New York Heart Association OPUS : orbofiban in patients with unstable coronary syndromes OR : odds ratio PaCO2 : mixed expired volume of alveolar and dead space gas PAH : pulmonary arterial hypertension PETCO2 : end-tidal expiratory CO2 pressure PCI : percutaneous coronary intervention PDA : personal digital assistant POISE : PeriOperative ISchaemic Evaluation trial QUO-VADIS : QUinapril On Vascular ACE and Determinants of ISchemia ROC : receiver operating characteristic SD : standard deviation SMVT : sustained monomorphic ventricular tachycardia SPECT : single photon emission computed tomography SPVT : sustained polymorphic ventricular tachycardia STEMI : ST-segment elevation myocardial infarction SVT : supraventricular tachycardia SYNTAX : synergy between percutaneous coronary intervention with taxus and cardiac surgery TACTICS : treat angina with aggrastat and determine cost of therapy with an invasive or conservative strategy TIA : transient ischaemic attack TIMI : thrombolysis in myocardial infarction TOE : transoesophageal echocardiography UFH : unfractionated heparin VCO2 : carbon dioxide production VE : minute ventilation VHD : valvular heart disease VKA : vitamin K antagonist VO2 : oxygen consumption VPB : ventricular premature beat VT : ventricular tachycardia Guidelines and Expert Consensus Documents aim to present management and recommendations based on the relevant evidence on a particular subject in order to help physicians to select the best possible management strategies for the individual patient suffering from a specific condition, taking into account not only the impact on outcome, but also the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines are no substitutes for textbooks. The legal implications of medical guidelines have been discussed previously.1 A great number of Guidelines and Expert Consensus Documents have been issued in recent years by the European Society of Cardiology (ESC) and also by other organizations or related societies. Because of the impact on clinical practice, quality criteria for development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC guidelines and Expert Consensus Documents can be found on the ESC website in the guidelines section (www.escardio.org). In brief, experts in the field are selected and undertake a comprehensive review of the published evidence for management and/or prevention of a given condition. …

Myocardial Homing of Nonmobilized Peripheral‐Blood CD34+ Cells After Intracoronary Injection

Granulocyte– colony‐stimulating factor administered for autologous hematopoietic stem cell isolation from blood may favor restenosis in patients implanted after acute myocardial infarction (AMI). We therefore tested the isolation of peripheral‐blood CD34+ cells without mobilization in six patients with AMI. After large‐volume cytapheresis and positive CD34+ cell selection, 3.6 to 27.6 million CD34+ cells were obtained. We performed intra‐coronary implantation of these cells and recorded no restenosis or arrhythmia. We used positron emission tomography (PET) to assess myocardial‐labeled CD34+ cell homing, which accounted for 5.5% of injected cells 1 hour after implantation. In conclusion, large amounts of CD34+ cells, in the range reported in previous studies, can be obtained from nonmobilized peripheral blood. PET with [18F]‐fluorodeoxyglucose cell labeling is an efficient imaging method for homing assessment.

Acute Effects of Passive Smoking on Peripheral Vascular Function

Environmental tobacco smoke (ETS) acutely affects peripheral and coronary vascular tone. Whether ETS exerts specific deleterious effects on aortic wave reflection through nicotine exposure, whether they persist after ETS cessation, and whether the smoke environment impairs microvascular function and increases asymmetrical dimethyl-arginine levels are not known. We tested these hypotheses in a randomized, crossover study design in 11 healthy male nonsmokers. The effects of 1 hour of exposure to ETS, as compared with a nontobacco smoke and normal air, on augmentation index corrected for heart rate and skin microvascular hyperemia to local heating were examined. Augmentation index increased both during (P=0.01) and after (P<0.01) the ETS session but remained unchanged in the nontobacco smoke session when compared with normal air. Nicotine levels after the exposure were related to the peak rise in augmentation index (r=0.84; P<0.01), denoting a predominant role of nicotine in ETS vascular effects. This was confirmed in a second set of experiments (n=14), where the sublingual administration of nicotine was associated with an acute impairment in wave reflection as compared with placebo (P=0.001). Both ETS and nontobacco smokes increased plasma asymmetrical dimethyl-arginine levels (P<0.001), but only ETS reduced the late rise in skin blood flow in response to heating (P=0.03). In conclusion, passive smoking specifically increases aortic wave reflection through a nicotine-dependent pathway and impairs microvascular function, even after the end of the exposure. However, both tobacco and nontobacco passive smoking inhalation increase plasma asymmetrical dimethyl-arginine levels.

Role of alpha-adrenergic coronary tone in exercise-induced angina pectoris

To provide more insight into the role of alpha-adrenergic coronary tone in exercise-induced angina, 9 patients with chronic stable angina underwent after coronary angiography a symptom-limited supine exercise test on a cyclo-ergometer. After recovery, phentolamine was directly injected into the most diseased vessel (2 mg in 5 minutes), and immediately thereafter the same exercise (identical workloads and exercise duration) was repeated. During exercise 1, heart rate (HR), mean blood pressure and cardiac index increased 51% (p less than 0.001), 23% (p less than 0.01) and 33% (p less than 0.01), respectively, and pulmonary artery wedge pressure (PA wedge) increased from 9 +/- 1 to 26 +/- 2 mm Hg (p less than 0.001). After intracoronary injection of phentolamine, control values (including PA wedge) at rest did not change significantly. During exercise 2, HR, mean blood pressure and cardiac index increased in a similar way--50% (p less than 0.001), 25% (p less than 0.01) and 40% (p less than 0.01), respectively; however the increase in PA wedge was less (p less than 0.01). ST-segment depression at the end of exercise 2 was smaller for identical workloads and double products: 1.5 +/- 0.3 mm vs 2.5 +/- 0.3 mm (p less than 0.01). ST/HR slope in exercise 2 also decreased 51% (p less than 0.01). These results show a less severe ischemic response after intracoronary alpha blockade and argue for an improvement in coronary blood supply.

Ramipril Prevents Endothelial Dysfunction Induced by Oxidized Low-Density Lipoproteins A Bradykinin-Dependent Mechanism

We wished to determine whether the acute toxic effects of oxidized LDL are attenuated in aortas isolated from rats chronically treated with an angiotensin-converting enzyme (ACE) inhibitor. In aortic rings incubated with human oxidized LDL (300 microg/mL), the endothelium-dependent relaxations to acetylcholine were attenuated, but not those to A23187 and to nitroprusside. This toxic effect of oxidized LDL was completely prevented in preparations coincubated with oxidized LDL and the nitric oxide (NO) precursor L-arginine (0.3 mmol/L). In aortas isolated from rats orally treated for 6 weeks with 10 mg/kg ramipril (group 1) or 1 mg/kg ramipril (group 2), this toxic effect of oxidized LDL was also markedly attenuated. In contrast, in aortas isolated from rats cotreated with ramipril (10 mg/kg) for 6 weeks and subcutaneous injections of Hoe 140 (a B2 kinin antagonist), 500 microg/kg per day for the last 2 weeks (group 3) or from rats orally treated for 6 weeks with losartan (an AT1-type angiotensin II receptor antagonist), 20 mg/kg (group 4), the inhibitory effect of oxidized LDL on acetylcholine-induced relaxations was similar to that observed in the control group (group 5). Moreover, long-term treatment with ramipril increased relaxations to acetylcholine in groups 1 and 2 and also relaxations to A23187 and aortic cGMP content in group 1, suggesting an enhanced NO availability. Thus, the protective effect of long-term ACE inhibition against the acute vascular toxicity of oxidized LDL is bradykinin dependent and seems to involve a facilitation of NO release via endothelial B2 kinin receptors.

Acute Exposure to Diesel Exhaust Impairs Nitric Oxide–Mediated Endothelial Vasomotor Function by Increasing Endothelial Oxidative Stress

Exposure to diesel exhaust was recently identified as an important cardiovascular risk factor, but whether it impairs nitric oxide (NO)–mediated endothelial function and increases production of reactive oxygen species (ROS) in endothelial cells is not known. We tested these hypotheses in a randomized, controlled, crossover study in healthy male volunteers exposed to ambient and polluted air (n=12). The effects of skin microvascular hyperemic provocative tests, including local heating and iontophoresis of acetylcholine and sodium nitroprusside, were assessed using a laser Doppler imager. Before local heating, skin was pretreated by iontophoresis of either a specific NO–synthase inhibitor (L-N-arginine-methyl-ester) or a saline solution (Control). ROS production was measured by chemiluminescence using the lucigenin technique in human umbilical vein endothelial cells preincubated with serum from 5 of the subjects. Exposure to diesel exhaust reduced acetylcholine-induced vasodilation (P<0.01) but did not affect vasodilation with sodium nitroprusside. Moreover, the acetylcholine/sodium nitroprusside vasodilation ratio decreased from 1.51±0.1 to 1.06±0.07 (P<0.01) and was correlated to inhaled particulate matter 2.5 (r=−0.55; P<0.01). NO–mediated skin thermal vasodilatation decreased from 466±264% to 29±123% (P<0.05). ROS production was increased after polluted air exposure (P<0.01) and was correlated with the total amount of inhaled particulate matter <2.5 &mgr;m (PM2.5). In healthy subjects, acute experimental exposure to diesel exhaust impaired NO–mediated endothelial vasomotor function and promoted ROS generation in endothelial cells. Increased PM2.5 inhalation enhances microvascular dysfunction and ROS production.

Myocardial homing and coronary endothelial function after autologous blood CD34+ progenitor cells intracoronary injection in the chronic phase of myocardial infarction.

Transcoronary transplantation of progenitor cells has been proposed as a novel therapy for ischemic heart failure. The primary aims were to assess the feasibility of obtaining CD34+ cells from blood without mobilization in chronic conditions and to compare homing with results reported in acute conditions. We also evaluated the effect of CD34+ on endothelial function. In 7 patients with a history of an anterior myocardial infarction (20 ± 2 months), a large amount of CD34+ (18.2 ± 3.0 × 106) were obtained and an intracoronary infusion into the left anterior descending artery via an over-the-wire balloon catheter was performed. Myocardial homing involved 3.2% ± 0.6% of injected cells. Endothelial function studied with increasing doses of bradykinin was not significantly modified after 3 months. In the treated group, compared with 5 nonrandomized control patients with a similar clinical history, the only echocardiographic significant change (2-way analysis of variance) was a decrease in end-systolic volume (P < 0.03). In conclusion, large amounts of CD34+ cells can be obtained from blood, without mobilization, in the chronic phase of myocardial infarction. As reported in the acute situation 1 hour after treatment, intracoronary infusion of CD34+ cells results in myocardial homing of a few percents of the cells. In this small group of patients, no effect of this therapy is detected on the endothelial function and only marginal changes are observed on echocardiographic parameters.

Absence of nitrate tolerance after long-term treatment with ramipril: an endothelium-dependent mechanism.

To determine whether nitrate tolerance is attenuated on aortas isolated from rats treated in the long term with an angiotensin-converting enzyme (ACE) inhibitor, five groups of rats were studied in parallel. Group 1 received ramipril, 1 mg/ kg/day, p.o., for 6 weeks; group 2 received ramipril at the same dose for 4 weeks, and the last 2 weeks, a cotreatment with ramipril plus HOE 140 (a bradykinin B2 antagonist, 500 microg/ kg/day, s.c. injections); group 3 received losartan, 2 mg/kg/day, p.o., for 6 weeks; group 4 received losartan at the same dose, and the last 2 weeks, a cotreatment with losartan plus HOE 140; and group 5 served as control. Rings of thoracic aorta from these groups were studied in organ baths. After nitroglycerin preincubation (10 microM for 30 min) in vitro, the dose-response curves to nitroglycerin were significantly shifted to the right in the control group but not in group 1. This protective effect was partially present in group 3; it was completely abolished in groups 2 and 4. In groups 1 and 3, it also was abolished after nitric oxide synthase (cNOS) inhibition (L-NMMA incubation) or removal of the endothelium. Superoxide anion accumulation (assessed by lucigenin chemiluminescence) was increased by nitroglycerin incubation in the control group but not in groups 1 and 3. After in vivo exposure to nitroglycerin (50 mg/kg subcutaneously twice daily for 4 days), this protection against nitrate tolerance also was observed in groups 1 and 3. Thus long-term ACE inhibition prevents nitrate tolerance by an endothelium-dependent mechanism involving mainly an enhanced NO availability via B2-kinin receptor. This effect on the cNOS pathway seems to attenuate the superoxide anion accumulation induced by nitroglycerin exposure (probably via a downregulation of oxidative enzyme).

Rosuvastatin treatment protects against nitrate-induced oxidative stress.

Nitrate tolerance is associated with an enhanced superoxide anion production and can be attenuated by statins, which interact with the 2 main [eNOS and NAD(P)H oxidase] pathways involved in producing this oxidative stress. Three groups of normocholesterolemic rats were treated: group 1 received rosuvastatin (10 mg/kg/d PO) for 5 weeks and in the last 3 days cotreatment with nitroglycerin (NTG 50 mg/kg/d, subcutaneous injections BID); group 2 received only NTG (50 mg/kg/d BID for the last 3 days); and group 3 served as control. Rings of thoracic aortas from these groups were studied in organ baths. Relaxations to NTG (0.1 nM to 0.1 mM) were determined on phenylephrine-preconstricted rings and O2− production (RLU/10 s/mg dry weight) was assessed by lucigenin and the luminol analogue (L-012) chemiluminescence technique. In group 2 (NTG), the concentration-response curves to NTG were significantly shifted to the right: the pD2 (−log NTG concentration evoking a half-maximal relaxation) was 6.75 ± 0.06 (n = 7) versus 7.75 ± 0.07 (n = 7) in group 3 (not exposed to NTG, P < 0.05); O2− production was enhanced (10,060 ± 1,205, n = 7 versus 5,235 ± 1,052, n = 7; P < 0.05). In contrast, in group 1, the rightward shift was attenuated: pD2 value was 7.20 ± 0.10 (n = 8), P < 0.05 versus group 2; O2− production was decreased (5911 ± 663; n = 9, P < 0.05 versus group 2). In addition, before NTG exposure, rosuvastatin treatment decreased p22phox [the essential NAD(P)H oxidase subunit] abundance in the aortic wall and decreased NAD(P)H oxidase activity. In contrast, this treatment did not alter either eNOS abundance or the basal release of endothelium-derived NO. Interestingly, in vivo treatment with apocynin, an NAD(P)H oxidase inhibitor, produced a protection similar to that with rosuvastatin. Long-term rosuvastatin treatment protects against nitrate tolerance in the rat aorta by counteracting NTG-induced increase in O2− production. This protection seems to involve a direct interaction with the NAD(P)H oxidase pathway rather than an up-regulation of the eNOS pathway.

Prevention of Nitrate Tolerance by Long-Term Treatment with Statins

AbstractRecent studies have shown that statins seem to upregulate the endothelial NO synthase pathway (eNOS) and may, therefore, enhance NO availability, a direct scavenger of O2− and an inhibitor of oxidative enzymes. Methods. To assess whether the oxidative stress produced by an in vivo exposure to nitroglycerin (NTG) is attenuated by statins, 4 groups of normocholesterolemic rats were treated; group 1 received pravastatin (20 mg/kg/d p.o) and group 2 atorvastatin (10 mg/kg/d) both for 5 weeks and the last 3 days, a cotreatment with the statin plus NTG (50 mg/kg/d, s.c. injections b.i.d.); group 3 (NTG) received only NTG (50 mg/kg/d, b.i.d. for 3 days) and group 4 served as control. Rings of thoracic aortas from these groups were studied in organ baths. Relaxations to NTG (0.1 nM to 0.1 mM) were determined on phenylephrine-preconstricted rings and O2− production (counts/10 s/mg) was assessed by lucigenin chemiluminescence technique. Results. In vivo NTG exposure induced a rightward shift of the concentration-response curves to NTG: the pD2 (−log NTG concentration evoking a half maximal relaxation) was 5.8 ± 0.3 (n = 7) vs. 7.2 ± 0.2 in the control group (not exposed to NTG, n = 7) and O2− production was enhanced (1259 ± 71 vs. 787 ± 76, (n = 5) P < .05). In contrast, groups 1 (n = 7) and 2 (n = 7) behaved as the control group (pD2 values were 7.4 ± 0.1 (n = 7) and 6.9 ± 0.1 (n = 7); O2− production was 721 ± 109 and 647 ± 121). The protective effect on nitrate tolerance disappeared when L-NAME (an eNOS inhibitor, 100 mg/kg/d) was co-administered with NTG in groups 1 and 2. Incubation of aortic rings with NAD(P)H (100 μM) also impaired the protective effect of both statins. Moreover, before NTG exposure, aortic cGMP content, reflecting EDNO availability, was significantly enhanced in group 1 (P < .05 vs. control). Conclusion. Long-term statin treatment protects against nitrate tolerance by counteracting NTG-induced increase in O2− production. Both eNOS pathway and NAD(P)H oxidases seem to be involved in this protective mechanism.