A prospective randomized trial comparing stenting to internal mammary artery grafting for proximal, isolated de novo left anterior coronary artery stenosis: the SIMA trial. Stenting vs Internal Mammary Artery.

OBJECTIVE: To compare coronary artery bypass grafting (CABG) with percutaneous transluminal coronary angioplasty (PTCA) in patients with proximal, isolated de novo left anterior descending coronary artery disease and left ventricular ejection fraction of 45%. PATIENTS AND METHODS: In the multicenter Stenting vs Internal Mammary Artery (SIMA) study, patients were randomly assigned to PTCA and stent implantation or to CABG (using the internal mammary artery). The primary clinical composite end point was event-free survival, including death, myocardial infarction, and the need for additional revascularization. Secondary end points were functional class, antianginal treatment, and quality of life. Analyses were by intention to treat. RESULTS: Of 123 patients who accepted randomization, 59 underwent CABG, and 62 were treated with stent implantation (2 patients were excluded because of protocol violation). At a mean +/- SD follow-up of 2.4+/-0.9 years, a primary end point had occurred in 19 patients (31%) in the stent group and in 4 (7%) in the CABG group (P<.001). This significant difference in clinical outcome is due to a higher incidence of additional revascularization in the stent group, the incidence of death and myocardial infarction being similar (7% vs 7%, respectively; P=.90). The functional class, need for antianginal drug, and quality-of-life assessment showed no significant differences. CONCLUSIONS: Both stent implantation and CABG are safe and highly effective treatments to relieve symptoms in patients with isolated, proximal left anterior descending coronary artery stenosis. Both are associated with a low and comparable incidence of death and myocardial infarction. However, similar to PTCA alone, a percutaneous approach using elective stent placement remains hampered by a higher need for repeated intervention because of restenosis.

Percutaneous closure of patent foramen ovale in patients with paradoxical embolism: long-term risk of recurrent thromboembolic events.

BACKGROUND: Patients with a patent foramen ovale (PFO) and paradoxical embolism are at risk for recurrent thromboembolic events. This study investigated the long-term risk of recurrent thromboembolic events in patients with PFO and paradoxical embolism after percutaneous PFO closure. METHODS AND RESULTS: Since 1994, a total of 80 patients with PFO and at least 1 paradoxical embolic event (transient ischemic attack [TIA], cerebrovascular accident [CVA], peripheral embolism) have undergone percutaneous PFO closure with 5 different devices. There were 30 women and 50 men, with a mean age of 52+/-12 years. Sixty patients had only a PFO, whereas 20 patients had both a PFO and an atrial septal aneurysm. The implantation procedure was successful in 78 patients (98%). During 5 years of follow-up (mean, 1.6+/-1.4 years; range, 0.1 to 5.0 years), the actuarial annual risk to suffer a recurrent thromboembolic event was 2.5% for TIA, 0% for CVA, 0.9% for peripheral emboli, and 3.4% for the combined end point of TIA, CVA, or peripheral embolism. A postprocedural shunt was a predictor of recurrent paradoxical embolism (RR, 4.2; 95% CI, 1.1 to 17.8; P=0.03). The risk for recurrent thromboembolic events in patients with both atrial septal aneurysm and PFO was not significantly increased compared with patients with only PFO (RR, 1.0; 95% CI, 0.2 to 4.7; P=0.95). CONCLUSIONS: Percutaneous PFO closure appears to be a promising technique in the prevention of recurrent systemic thromboembolism in patients with a PFO after a first event. Prospective studies comparing percutaneous PFO closure with antithrombotic medications or surgery must define its therapeutic value.

Physiologically assessed coronary collateral flow and intracoronary growth factor concentrations in patients with 1- to 3-vessel coronary artery disease.

BACKGROUND: The purpose of this study was to test the hypothesis that there is a relation between collateral flow and intracoronary concentrations of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and that the combined concentrations of both growth factors and the extent of coronary artery disease (CAD) play a role as covariables in such an association. METHODS AND RESULTS: In 76 patients undergoing balloon angioplasty, a collateral flow index (CFI, no units) was determined with sensor-tipped guidewires. Simultaneously, serum concentrations of bFGF and VEGF, obtained at the aortic root from the ostium of the collateralized coronary artery (n = 76) and from the distal position of the occluded coronary artery (n = 34), were determined. There was a direct correlation between CFI and distal VEGF (r = 0.33, P = 0.05) but not bFGF concentrations. Focusing on the proximal sampling site, there was a direct correlation between CFI and both bFGF (r = 0.29, P = 0.01) and VEGF concentrations (r = 0.44, P < 0.0001). The sum of the concentrations of both growth factors was directly associated with CFI irrespective of the proximal (r = 0.51, P < 0.0001) or distal sampling site (r = 0.34, P = 0.048). There was a trend toward higher proximal VEGF concentrations in patients with higher numbers of coronary stenotic lesions (r = 0.25, P = 0.03). CONCLUSIONS: In patients with CAD, there is an association between a directly measured index of collateral flow and intracoronary concentrations of bFGF and VEGF. This direct relation is dependent on the site of blood sampling within the coronary artery tree. The association is closest when the combined bFGF and VEGF concentrations are taken into account. In the case of VEGF, it is influenced by the degree of coronary atherosclerosis.

[Invasive diagnosis of coronary heart disease in patients over 75 years old]. / Invasive Abklärung der koronaren Herzkrankheit bei über 75-jährigen Patienten.

Between January 1, 1993, and August 31, 1995, 268 patients over 75 years underwent coronary angiography at the University Hospital of Bern. Their clinical reports were analyzed in order to determine whether invasive diagnosis of coronary artery disease (CAD) is justifiable also in the elderly considering risks and complications. The main indication for coronary angiography were symptoms of ischemic heart disease. Twenty-nine underwent the procedure for planned cardiac surgery, mostly valve replacement. In 79% of patients, coronary angiography revealed CAD. In the remaining 21% there were no significant coronary stenoses, but 82% of them had valvular heart disease. Only 4% had neither coronary nor valvular heart disease. Following coronary angiography 63% of patients had a therapeutical intervention: 24% coronary angioplasty (PTCA), 13% bypass-grafting, 17% valve replacement, 8% combined surgery (revascularization and valve-replacement), and 1% another intervention. Four percent had no cardiac disease, 1% died before a planned surgery. The remaining 32% were continued on medical therapy. As indicators of appropriateness and success of the invasive procedure the rates of complications and the duration of hospitalization were analyzed. The incidence of deaths, myocardial infarctions, cerebral complications, and arrhythmias was five to ten times higher for cardiac surgery than for PTCA or conservative treatment. Invasive diagnosis and therapy of CAD in patients over 75 years can nevertheless be reasonable and successful if the decision is taken carefully considering risk factors and concomitant disease.

Is the development of myocardial tolerance to repeated ischemia in humans due to preconditioning or to collateral recruitment?

OBJECTIVES: The purpose of this study in patients with quantitatively determined, poorly developed coronary collaterals was to assess the contribution of ischemic as well as adenosine-induced preconditioning and of collateral recruitment to the development of tolerance against repetitive myocardial ischemia. BACKGROUND: The development of myocardial tolerance to repeated ischemia is nowadays interpreted to be due to biochemical adaptation (i.e., ischemic preconditioning). METHODS: In 30 patients undergoing percutaneous transluminal coronary angioplasty, myocardial adaptation to ischemia was measured using intracoronary (i.c.) electrocardiographic (ECG) ST segment elevation changes obtained from a 0.014-in. (0.036 cm) pressure guidewire positioned distal to the stenosis during three subsequent 2-min balloon occlusions. Simultaneously, an i.c. pressure-derived collateral flow index (CFI, no unit) was determined as the ratio between distal occlusive minus central venous pressure divided by the mean aortic minus central venous pressure. The study patients were divided into two groups according to the pretreatment with i.c. adenosine (2.4 mg/min for 10 min starting 20 min before the first occlusion, n = 15) or with normal saline (control group, n = 15). RESULTS: Collateral flow index at the first occlusion was not different between the groups (0.15 +/- 0.10 in the adenosine group and 0.13 +/- 0.11 in the control group, p = NS), and it increased significantly and similarly to 0.20 +/- 0.14 and to 0.19 +/- 0.10, respectively (p < 0.01) during the third occlusion. The i.c. ECG ST elevation (normalized for the QRS amplitude) was not different between the two groups at the first occlusion (0.25 +/- 0.13 in the adenosine group, 0.25 +/- 0.19 in the control group). It decreased significantly during subsequent coronary occlusions to 0.20 +/- 0.15 and to 0.17 +/- 0.13, respectively. There was a correlation between the change in CFI (first to third occlusion; deltaCFI) and the respective ST elevation shift (deltaST): deltaST = -0.02 to 0.78 x deltaCFI; r = 0.54, p = 0.02. CONCLUSIONS: Even in patients with few coronary collaterals, the myocardial adaptation to repetitive ischemia is closely related to collateral recruitment. Pharmacologic preconditioning using a treatment with i.c. adenosine before angioplasty does not occur. The variable responses of ECG signs of ischemic adaptation to collateral channel opening suggest that ischemic preconditioning is a relevant factor in the development of ischemic tolerance.

Coronary collateral quantitation in patients with coronary artery disease using intravascular flow velocity or pressure measurements.

OBJECTIVES: This study evaluated two methods for the quantitative measurement of collaterals using intracoronary (IC) blood flow velocity or pressure measurements. BACKGROUND: The extent of myocardial necrosis after coronary artery occlusion is substantially influenced by the collateral circulation. So far, qualitative methods have been available to assess the human coronary collateral circulation, thus restraining the conclusive investigation of, for example, therapies to promote collateral development. METHODS: Fifty-one patients with a coronary artery stenosis to be treated by percutaneous transluminal coronary angioplasty (PTCA) were investigated using IC PTCA guidewire-based Doppler and pressure sensors positioned distal to the stenosis. Simultaneous measurements of aortic pressure, IC velocity and pressure distal to the stenosis during and after PTCA provided the variables for calculating collateral flow indices (CFIv and CFIp) that express collateral flow as a fraction of flow via the patent vessel. Both CFIv and CFIp were compared with conventional methods for collateral assessment, among them ST-segment changes >1 mm on IC and surface electrocardiogram (ECG) at PTCA. Also, CFIv and CFIp were compared with each other. RESULTS: In 11 patients without ECG signs of ischemia during PTCA (sufficient collaterals), relative collateral flow amounted to 46% as determined by Doppler and pressure wire. Patients with insufficient collaterals (n=40) had relative collateral flow values of 18%. Using a threshold of CFI=30%, sufficient and insufficient collaterals could be diagnosed with 100% sensitivity and 93% specificity by IC Doppler, and 75% sensitivity and 92% specificity by IC pressure measurements. The agreement between Doppler and pressure measurements was good: CFIv=0.08 + 0.8 CFIp, r=0.80, p=0.0001. CONCLUSIONS: Intracoronary flow velocity or pressure measurements during routine PTCA represent an accurate and, at last, quantitative method for assessing the coronary collateral circulation in humans.

Prolonged heparin after uncomplicated coronary interventions: a prospective, randomized trial.

BACKGROUND: Continuous heparin infusion after percutaneous transluminal coronary angioplasty (PTCA) procedures prolongs the hospital stay and could increase the occurrence of bleeding complications. The aim of this randomized trial was to evaluate whether omission of heparin infusion after uncomplicated coronary interventions in patients with stable and unstable angina with or without stent implantation increased the incidence of acute cardiac complications. METHODS AND RESULTS: A total of 191 consecutive patients who underwent successful PTCA were randomly assigned to receive either prolonged heparin (heparin group) or no postprocedure heparin (control group). The 2 treatment groups were comparable with respect to clinical and angiographic characteristics. Stents were used in 36% of the control group and in 33% of the heparin group. Cardiac complications occurred in 8 (4%) patients. Four (4%) patients in the control group and 3 (3%) patients in the heparin group had a myocardial infarction. One patient in the control group died 3 days after the intervention. No patient in either group needed a repeat revascularization during the target hospitalization. Peripheral vascular complications in the control and heparin groups occurred in 1% and 3% of the patients, respectively. CONCLUSIONS: Omission of heparin after successful PTCA with or without stent implantation in patients with stable and unstable angina did not significantly increase the incidence of acute cardiac complications. It allows for early sheath removal and patient discharge and saves costs. This study, combined with other small studies in the field, provides strong evidence that heparin should not be used routinely.

[The Magnum wire for the angioplasty of coronary occlusions and stenoses]. / "Magnum wire" per l'angioplastica delle occlusioni e delle stenosi coronariche.

The "Magnum wire" is a stiff shaft, blunt tip wire constructed for recanalization of total coronary occlusions. Smaller series have demonstrated superior qualities if compared to conventional wires. The purpose of this study was to analyze its efficacy in total and nontotal lesions in a large number of consecutive procedures. A database analysis identified the use of the Magnum wire in 569 procedures from October 1992 to February 1995, which accounted for 26% of all angioplasties during the time period at our Institution. There were 347 total occlusions and 222 nontotal occlusions. Technical success was achieved in 69% of total occlusions and 90% of subtotal occlusions. Procedural success was recorded in 58 and 75%, respectively. Stents were implanted in 29 patients with total occlusion (8%) and 19 patients with nontotal lesions (9%). Acute occlusion of the treated lesion occurred in 4.5% of patients with nontotal lesion and 1.5% of the patients with total occlusion. In conclusion, the Magnum wire is an efficient tool for angioplasty of total occlusions and severe nonocclusive stenoses. In light of the complexity of the attempted lesions, achieved success rates were remarkable.

Functional assessment of collaterals in the human coronary circulation.

The coronary collateral circulation is an alternative source of blood supply to a myocardial area jeopardized by the failure of the stenotic or occluded vessel to provide enough blood flow to this region. Until recently, only qualitative or semiqualitative methods have been available for the assessment of the coronary collateral circulation in humans, such as the patient's history of walk-through angina pectoris, the registration of intracoronary ECG signs for myocardial ischaemia or angina pectoris during coronary occlusion, or coronary angiographic classification (score 0-3) of collaterals. Studies of coronary wedge pressure measurements distal of a balloon-occluded coronary artery and the recent advent of ultrathin pressure and Doppler angioplasty guidewires have made it possible to obtain pressure or flow velocity data in remote vascular areas and, thus, to calculate functional variables for coronary collateral flow. Those coronary occlusive pressure- and flow velocity-derived parameters express collateral flow as a fraction of antegrade coronary flow during vessel patency of the collateral-receiving vessel. They are both interchangeable, and they have been validated in comparison to 'traditional' methods and against each other. The possibility of accurately measuring coronary collateral flow indices in humans undergoing coronary balloon angioplasty opens areas of investigation of the pathogenesis, pathophysiology and therapeutic promotion of the collateral circulation previously reserved for exclusively experimental studies. The purpose of this article is to review several clinically available methods for the functional characterization of the coronary collateral circulation.

[Interventional treatment of heart valve diseases]. / Interventionelle Behandlung von Klappenvitien.

Percutaneous balloon valvuloplasty of stenoses has been introduced into medical practice in the late 70ies. Over the past decade, the method has evolved to a valid alternative to valve surgery in selected cases. Balloon valvuloplasty of isolated mitral stenosis is to date the therapy of choice and yields results comparable to those of surgery. It is even superior in only moderately diseased valves. However, the most frequent valve stenosis, that is aortic stenosis of the elderly, is not suitable for balloon dilatation. Dilatation of congenital aortic stenosis can be attempted if the valve is bicuspid or tricuspid. The recurrence rates for valvular stenoses after valvuloplasty are similar to those after surgical commissurotomy.

[Myocardial revascularization in geriatric patients]. / Myokardrevaskularisation bei geriatrischen Patienten.

The results of percutaneous transluminal coronary angioplasty (PTCA) in 71 patients over 75 years of age were retrospectively analyzed and compared with those of 55 patients aged over 75 who underwent surgical revascularization (CABG) during the same time period (1992-1995). The main indication for revascularization was unstable angina. The clinical success in PTCA patients was 92%, with a lesion success rate of 93%. Major cardiac complications occurred in 5% of patients with an in-hospital mortality of 1%. The mean hospital stay was 4 days. During a follow-up period of 16 (range 1-36) months, 23% of patients treated with PTCA needed repeat revascularization (17% PTCA, 6% CABG) and 4 patients (6%) suffered nonfatal myocardial infarction. In-hospital mortality and complications were higher among the surgically treated patients (mortality 7%, major complications 45%), a fact probably related to their poorer clinical condition preoperatively. Repeat revascularization rate in the surgically treated group was 2%. The long-term mortality rate in both groups was 10%. Among long-term survivors, 92% of patients indicated that revascularization (PTCA or CABG) improved their quality of life. More than 80% led normal lives, and > 90% would undergo a second procedure if needed. In selected patients aged over 75, PTCA has a high immediate success rate with low complications and mortality. Long-term recurrence rate is high, however, and repeat revascularizations are frequent. Patient satisfaction after myocardial revascularization (PTCA or CABG) is excellent and the majority of elderly patients can lead an active and independent life.