The previously proposed classification schemes are outdated and need to be changed for application in current angioplasty practice. Analyzing specific lesion morphologic characteristics rather than applying a simple lesion classification score when evaluating angioplasty outcome may be more useful because it provides a more precise profile of the lesion and allows better patient stratification and selection.

No abstract

Objective-To study the determinants of success of coronary angioplasty in patients with chronic total occlusions, and to formulate a multiple logistic regression model to improve selection of patients. Design-A retrospective analysis of clinical and angiographic data on a consecutive series of patients.Patients-312 patients (mean age 55, range 31 to 79 years, 86% men) who underwent coronary angioplasty procedure for a chronic -total occlusion between 1981 and 1992. Results-Procedural success was achieved in 191 lesions (61.2%). A major complication occurred in six patients (1.90!6). Multiple stepwise logistic regression analysis identified the presence of bridging coliaterals (p < 0.001), the absence of a tapered entry configuration (p < 0.001), estimated duration of occlusion of greater than three months (p = 0.001), and a vessel diameter of less than 3 mm (p = 0.003) as independent predictors of procedural failure. The logistic regression model was used to classify patients into groups of high, intermediate, and low probability of procedural success with cut off points of 70% and 30%. The predictive value for procedural success (probability 70%/6) was 91% (95% confidence intervals (95% CI) 83% to 96%) and predictive value for procedural failure (probability <30%) was 81% (95% CI 64% to 92%). Conclusions-Percutaneous transluminal coronary angioplasty of chronic total occlusions is associated with a low risk of acute complication. Procedural success is influenced by easily identifiable clinical and angiographic features and the multiple regression model described may help to improve selection of patients. (Br Heart J 1993;70:126-13 1) Since the introduction of percutaneous transluminal coronary angioplasty by Gruentzig in 1978,1 the procedure has been applied to increasingly complex lesions including occluded vessels.2' Coronary angioplasty of chronic total occlusions is recognised to have a lower primary success rate ranging from 53% to 73%," and contributes to the failure to achieve complete revascularisation among many patients with multivessel disease.78 Despite this relatively low initial success rate, recanalisation of chronic total occlusions by coronary angioplasty has become an accepted procedure and the prevalence has increased from about 2% to 10% of the total number of coronary angioplasties performed in large centres.9 At present, the ability to predict the likelihood of procedural success for a particular lesion is poor. This study reports on the acute success and complication rates of coronary angioplasty of chronic total occlusions on 312 consecutive patients. It also describes a multiple logistic regression model incorporating clinical and angiographic data to predict probability of procedural success for a particular lesion. Patients and methods ANGIOPLASTY PROCEDURECoronary angioplasty was performed according to a previously described protocol."3 More than 60% of the procedures were performed by a single operator. Steerable guide wire systems have been in use since 1984. The techniq...

No abstract

Most patients who were satisfied with long term pacing in VVI mode benefited from upgrading to DDD mode pacing suggesting the existence of "subclinical" pacemaker syndrome in up to 75% of such patients. The DDI mode offered little subjective or objective benefit over VVI mode in this population and should be reserved for patients with paroxysmal atrial arrhythmias. VVI mode pacing should be used only for patients with very intermittent symptomatic bradycardia or atrial fibrillation with a good chronotropic response during exercise.

The treatment of complete heart block by means of an artificial pacemaker is now well established, but there is still considerable uncertainty as to the best heart rate and the relative merits of fixed or variable rate units. al., 1963). Preliminary studies showed that under constant conditions with patients at rest five measurements of relative cardiac ouput could be made with results that differed by 7 per cent or less. During the determination of output-time curves cardiac output measurements were made at two-minute intervals: during the determination of rate-output curves the output was measured four minutes after each alteration in pacemaker rate. Conversion of relative output to litres/min. was made by calibration of the first curve by means of control and end-tail blood samples: the absolute values are approximate.Resting measurements were made when the patients were sitting with the trunk supported at about 45 degrees. Exercise studies were carried out on a bicycle ergometer (Gabe and Robinson, 1960), on which the power setting could be varied in steps of 5 Watts. Table I gives the approximate oxygen uptake (B. Robinson, 1963, personal communication) and equivalent activity of various settings on this apparatus.

The aim of this study was to compare, both subjectively and objectively, four modern rate-responsive pacing modes in a double-blind crossover design. Twenty-two patients, aged 18 to 81 years, had an activity-sensing dual chamber universal rate-responsive (DDDR) pacemaker implanted for treatment of high grade atrioventricular block and chronotropic incompetence. They were randomly programmed to VVIR (ventricular demand rate-responsive), DDIR (dual chamber demand rate-responsive), DDD (dual chamber universal) or DDDR (dual chamber universal rate-responsive) mode and assessed after 4 weeks of out-of-hospital activity. Five patients, all with VVIR pacing, requested early reprogramming. The DDDR mode was preferred by 59% of patients; the VVIR mode was the least acceptable mode in 73%. Perceived "general well-being," exercise capacity, functional status and symptoms were significantly worse in the VVIR than in dual rate-responsive modes. Exercise treadmill time was longer in DDDR mode (p less than 0.01), but similar in all other modes. During standardized daily activities, heart rate in VVIR and DDIR modes underresponded to mental stress. All rate-augmented modes overresponded to staircase descent, whereas the DDD mode significantly underresponded to staircase ascent. Echocardiography revealed no difference in chamber dimensions, left ventricular fractional shortening or pulmonary artery pressure in any mode. Cardiac output was greater at rest in the dual modes than in the VVIR mode (p = 0.006) but was similar at 120 beats/min. Beat to beat variability of cardiac output was greatest in VVIR mode (p less than 0.0001), with DDIR showing greater variability than DDD or DDDR modes (p less than 0.05). Mitral regurgitation estimated by Doppler color flow imaging was similar in all modes, but tricuspid regurgitation was significantly greater in VVIR than in dual modes (p less than 0.03). Subjects who preferred the DDDR mode and those who found the VVIR mode least acceptable had significantly greater increases in stroke volume when paced in the DDD mode than in the ventricular-inhibited (VVI) mode at rest (22%) when compared with subjects who preferred other modes (2%, p = 0.03). No other objective variable was predictive of subjective benefit from any rate-responsive pacing mode. Thus, dual sensor rate-responsive pacing (DDDR) is superior objectively and subjectively to single sensor (VVIR, DDIR and DDD) pacing and subjective benefit from dual chamber rate-augmented pacing is predictable echocardiographically.

No abstract