Percutaneous transluminal laser coronary angioplasty (PTLCA) was undertaken in five patients (four men and one woman, aged 44-72 years) with coronary artery stenosis. The vessel diameter was increased in all patients after PTLCA; complete ablation of the atheromatous plaque succeeded in three. In the other two the catheter could not be advanced across the entire stenotic region. After PTLCA the stenoses were 40-50% of normal lumen. Balloon dilatation was additionally done in all five patients. In three this caused dissection of the vessel wall distal to the stenosis and possible intracoronary thrombus formation: this would suggest that balloon dilatation after laser angioplasty is not recommendable. PTLCA widens the spectrum of invasive methods for treating coronary artery stenosis.

Coronary angiography in a 58-year-old man who had sustained an anterior-wall myocardial infarction demonstrated a myocardial bridge over the anterior interventricular branch as the only abnormal finding which, in the absence of any arteriosclerotic changes proximal or at the level of the bridge, suggests a causal relationship.

The vasoselectivity of new dihydropyridine calcium antagonists is much higher as compared to their prototype substance nifedipine. To investigate whether an equihypotensive dose of a new dihydropyridine has less negative inotropic properties in an intact circulation, nifedipine (NIF) and nisoldipine (NIS) were infused intravenously in an open-chest, anaesthetized rat model. The maximal isovolumic left ventricular pressure (LVPiso) and the maximal isovolumic rate of change of LV-pressure (dp/dt(max)iso) were determined to achieve load independent parameters of LV contractility. To evaluate the effect of the infused volume, the stability of the preparation and the hemodynamic effects of the drug-solvent, two groups with either infusion of isotonic NaCl-solution or 20% ethanol sewed as controls. NIF and NIS were infused in three equihypotensive doses within 7 min (NIF 250, 500, 1000 mu g/kg; NIS 12.5, 25, 50 mu g/kg). The decrease of the peripheral resistance for these doses was 74 +/- 6, 67 +/- 6, and 58 +/- 7% for NIF, and 78 +/- 7, 65 +/- 8, and 56 +/- 7% for NIS (p < 0.0001 for all groups). In the control groups the afterload remained unchanged. NIF-infusion resulted in a dose-dependent decrease of LVPiso at the end of the infusion period (in per cent of controls: NIF250 88 +/- 3%, p < 0.001; NIF500 74 +/- 3%, p < 0.001) as well as 15 min after the end of the infusion. In the same way dp/dt(max)iso decreased significantly after NIF at the end of infusion (NIF 250 82 +/- 6 %, p < 0.001; NIF500 61 +/- 8%, p < 0.001) and 15 min after the end of the infusion. After NIS-infusion the contractility parameters decreased slightly after the higher dosage (25 mu g/kg) at the end of the infusion period only (LVPiso 96 +/- 3%, p < 0.01; dp/dt(max)iso 93 +/- 5%, p < 0.01). There was no depressive effect on the isovolumic contractility parameters at the end of infusion of the lower dosage and 15 min after the drug-infusion of all dosages of NIS. Therefore, nisoldipine, as an example of a new dihydropyridine, has significantly less negative inotropic properties over a wide range of doses as compared to nifedipine in equihypotensive doses.

The vasoselectivity of new dihydropyridine calcium antagonists is much higher as compared to their prototype substance nifedipine. To investigate whether an equihypotensive dose of a new dihydropyridine has less negative inotropic properties in an intact circulation, nifedipine (NIF) and nisoldipine (NIS) were infused intravenously in an open-chest, anaesthetized rat model. The maximal isovolumic left ventricular pressure (LVPiso) and the maximal isovolumic rate of change of LV-pressure (dp/dtmaxiso) were determined to achieve load independent parameters of LV contractility. To evaluate the effect of the infused volume, the stability of the preparation and the hemodynamic effects of the drug-solvent, two groups with either infusion of isotonic NaCl-solution or 20% ethanol served as controls. NIF and NIS were infused in three equihypotensive doses within 7 min (NIF 250, 500, 1000 micrograms/kg; NIS 12.5, 25, 50 micrograms/kg). The decrease of the peripheral resistance of these doses was 74 +/- 6, 67 +/- 6, and 58 +/- 7% for NIF, and 78 +/- 7, 65 +/- 8, and 56 +/- 7% for NIS (p < 0.001 for all groups). In the control groups the afterload remained unchanged. NIF-infusion resulted in a dose-dependent decrease of LVPiso at the end of the infusion period (in percent of controls: NIF250 88 +/- 3%, p < 0.001; NIF500 74 +/- 3%, p < 0.001) as well as 15 min after the end of the infusion. In the same way dp/dtmaxiso decreased significantly after NIF at the end of infusion (NIF 250 82 +/- 6%, p < 0.001; NIF500 61 +/- 8%, p < 0.001) and 15 min after the end of the infusion. After NIS-infusion the contractility parameters decreased slightly after the higher dosage (25 micrograms/kg) at the end of the infusion period only (LVPiso 96 +/- 3%, p < 0.01; dp/dtmaxiso 93 +/- 5%, p < 0.01). There was no depressive effect on the isovolumic contractility parameters at the end of infusion of the lower dosage and 15 min after the drug-infusion of all dosages of NIS. Therefore, nisoldipine, as an example of a new dihydropyridine, has significantly less negative inotropic properties over a wide range of doses as compared to nifedipine in equihypotensive doses.

To compare the negative inotropic effects of the four dihydropyridine-calcium-channel-blockers nifedipine (NIF), isradipine (ISR), nisoldipine (NIS) and felodipine (FEL) in man, the drugs were infused within 30 min intravenously in an equihypotensive dosage (NIF 2 mg, ISR 0.5 mg, NIS 0.5 mg, FEL 0.6 mg; 10 patients in each group) in patients with coronary heart disease. As a control, an additional 1 0 patients received isotonic saline solution following an identical protocol. The afterload reduction was submaximal (reduction of peripheral resistance: NIF -23 +/- 9 %, ISR -24 +/- 10 %, NIS -28 +/- 6 %, FEL -27 +/- 6 %; no significant difference for group comparison) with a similar kinetic and a steady state of the afterload reduction after one-half of the infusion period to achieve a comparable sympathetic reflex activation. Preload parameters (PAP, LVEDP) were unchanged in all groups.A reflex tachycardia occurred in all treatment groups after 15 min of drug infusion. Due to its negative chronotropic properties, the reflex tachycardia was significantly attenuated after isradipin as compared to the other drugs (heart-rate changes: NIF +13 +/- 7 %, p < 0.01; ISR +4 +/- 7 %, not significant; NIS +20 +/- 10 %, p < 0.01; FEL +17 +/- 12 %, p < 0.01).Because of the baroreflex and sympathetic reflex activation the left-ventricular dp/dtmax increased after isradipine )+14 +/-10 %, p < 0.01) and nisoldipine (+16 +/- 13 %, p < 0.01). The lack of a significant dp/dtmax increase in spite of a comparable afterload reduction after felodipine (+5 +/- 8 %, not significant) or nifedipine (-3 +/- 6 %, not significant) must be a consequence of the cardiodepressive properties of these drugs. Therefore, in an equihypotensive dosage, the strongest negative inotropic effects were observed alter nifedipine, lesser effects after felodipine (p < 0.03), and the weakest cardio-depressive effects after isradipin (p < 0.01) and nisoldipine (P < 0.01).For clinical applications the lesser cardiodepressive properties of the new dihydropyridine-derivates should be advantageous in patients with already reduced left-ventricular performance or for use in combination with other negative inotropic drugs, e.g., betablockers.

To study the effect of heart rate changes on Doppler measurements of mitral valve area atrial pacing was performed in 14 patients with mitral stenosis and sinus rhythm. Continuous wave Doppler and haemodynamic measurements were performed simultaneously at rest and during pacing-induced tachycardia. (1) Mitral valve area was determined using the conventional pressure half time method. (2) Additionally, mitral valve area was calculated with a combined Doppler and thermodilution technique according to the continuity equation. (3) Simultaneous invasive measurements were used for calculation of the mitral valve area according to the Gorlin formula. With increasing heart rate (69 +/- 13-97 +/- 15-114 +/- 13 beats min-1) mitral valve area either determined by the continuity equation (1.0 +/- 0.2-1.0 +/- 0.3-1.1 +/- 0.4 cm2) or the Gorlin formula (1.2 +/- 0.3-1.2 +/- 0.4-1.3 +/- 0.4 cm2) remained constant. Both methods correlated closely not only at rest (r = 0.88, SEE = 0.11 cm2, P less than 0.001), but also during atrial pacing (first level: r = 0.95, SEE = 0.10 cm2, P less than 0.001, second level: r = 0.95, SEE = 0.13 cm2, P less than 0.001). In contrast, mitral valve area calculated according to the pressure half time method increased significantly during atrial pacing (1.0 +/- 0.3-1.8 +/- 0.5-2.0 +/- 0.5 cm2).(ABSTRACT TRUNCATED AT 250 WORDS)

The initial single center experience of percutaneous coronary excimer laser angioplasty is described for the first three series of 147 patients. Sixty patients were treated with a prototype 1.4-mm laser catheter, 40 patients with improved transmission devices, and the third series of 47 patients with an increased pulse width of the laser system allowing improved energy transmission. In 17 patients (12%) laser angioplasty could not be initiated due to inability to cross the lesion with the guidewire or to place the catheter coaxially within the vessel. In 32 patients (58%) of series 1, 11 patients (31%) of series 2, and 17 patients (43%) of series 3, additional balloon dilatation following laser treatment was necessary due to vessel closure (24%) or due to an insufficient angiographic result (35%). There was one death in series 1 (2%) and 2 (3%) each, one perforation in series 2 (3%), two transmural myocardial infarctions in series 1 (4%), and one myocardial infarction in series 2 (3%). During the 6-month follow-up period one patient in series 2 (2%), and one patient in series 3 (3%) died. Angiographic restenosis was found in 22, 12, and 11 patients of series 1 (40%), 2 (34%), and 3 (27%), respectively. No patient developed a transmural myocardial infarction. Thus, percutaneous coronary excimer laser angioplasty can be performed as a safe and feasible procedure in patients with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser and catheter technology have been considerably improved within the first 2 years of the clinical use of coronary excimer laser angioplasty. Furthermore, patient selection has changed due to increasing operator experience. We report on the acute- and long-term results achieved in 163 patients in three subgroups with different system parameters and catheter technology. In the initial series 1 (N:60) a prototype catheter with a diameter of 1.4 mm was used. In series 2 and 3, we employed improved transmission devices with 1.3, 1.5 or 1.8 mm. In series 3 the pulsewidth was increased from 60 ns to 115 ns. The target vessel was the LAD in 68%, the LCX in 10%, and the RCA in 21%. According to the AHA/ACC Lesion classification there were 13% type A, 26% type B1, 55% type B2, and 5% type C lesions. Stand-alone laser angioplasty was performed in 23/60 (38%), 24/40 (60%), and 34/64 (53%) in series 1, 2, and 3, respectively. Additional balloon angioplasty was necessary in 32, 11, and 21 interventions. Failure of laser angioplasty occurred in five patients of series 1 and 2, and nine patients of series 3. Frequently observed complications included coronary spasm in 18 to 32%, dissections in 16% to 33%, and vessel closure in 18 to 27%. Myocardial infarction occurred in three patients in the first and one patient of the second and third series. There was one in-hospital death in series 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)

In selected patients with calcific aortic stenosis, balloon valvuloplasty is an intermediate alternative to surgery. The effect of balloon valvuloplasty to increase valve area, however, is limited and the restenosis rate is high during follow-up. To improve the results and reduce the complication rate, a new device for valvuloplasty of calcific aortic stenosis was developed. This system consists of three expandable prongs mounted on a freely movable catheter tip. To evaluate the efficacy of this new device, valvuloplasty was performed in 10 patients with severe aortic stenosis intraoperatively just prior to valve replacement. Comparison was made with the results of conventional balloon dilatation performed in an additional 20 patients during surgery. Using the new device, the relative orifice area increased from 10 +/- 3% before to 20 +/- 6% following intervention. However, in only one patient was a considerable increase of static valve area (greater than 15%) found. The results were comparable to the effect of conventional balloon dilatation, which led to an increase of orifice area from 12 +/- 7% to 24 +/- 10%. With both systems, the best results were achieved in patients with aortic stenosis and significant commissural fusion. In contrast, in bicuspid or tricuspid valves without fused commissures the effect of the intervention was limited. Because complete obstruction of the aortic valve does not occur during dilatation, this new device might be superior to conventional balloon dilatation. Preselection of patients according to the morphology of the valve seems mandatory to improve the success and reduce the complication rate of valvuloplasty in aortic stenosis.

The incidence of coronary vasospasm during and following excimer laser atherectomy is considerable. The aim of this study was to investigate vasoconstriction of the target vessel during early follow-up angiography. In 50 patients an angiogram was performed 24 hours after intervention. Nineteen patients were treated with stand-alone laser atherectomy (group I), another 19 with laser and additional balloon angioplasty (group II) and 12 with balloon angioplasty alone (group III). Lumen diameter and percent stenosis before and after intracoronary application of 0.1 mg nitroglycerin were determined. The differences were compared between groups I, II and III, and for patients with (N = 14) and without (N = 24) vasospasm during laser atherectomy. There was a significant increase in lumen diameter, of 0.17 +/- 0.28 mm, after nitroglycerin in group I, of 0.18 +/- 0.29 mm in group II (P = 0.02) and of 0.03 +/- 0.21 mm in group III (ns). In patients with vasospasm during laser atherectomy the average increase in lumen diameter was 0.28 +/- 0.24 mm (P less than 0.01), and in patients without vasospasm 0.12 +/- 0.29 mm (P = 0.09). We conclude that one day after coronary excimer laser atherectomy intracoronary nitroglycerin significantly affects lumen diameter at the site of previous stenosis, an effect undetectable after balloon angioplasty. Thus, vasoconstriction after excimer laser ablation seems to be a common phenomenon and is prolonged in patients with vasospasm during the previous intervention.

To quantify valve area in mitral stenosis, a modified continuity equation method using continuous wave Doppler and thermodilution measurements was applied. In 14 patients with mitral stenosis and sinus rhythm (age: 49±11 years), transmitral flow velocity was recorded by continuous wave Doppler during right and left heart catheterization. Mitral valve area was calculated by three different methods: 1. According to the continuity equation, stroke volume (thermodilution technique) was divided by the registered time velocity integral of the mitral stenotic jet (continuous wave Doppler). 2. Mitral valve area was calculated by the pressure half-time method. 3. Simultaneous pulmonary capillary wedge and left ventricular pressure measurements were used for determination of mitral valve area according to the Gorlin formula. The mitral valve area determined by application of the continuity equation (y) showed a close correlation to the valve area calculated by the Gorlin equation (x):y=0.73x+0.12, SEE=0.11 cm2,r=0.88,P<0.001. In contrast, the correlation between mitral valve area determined by pressure half-time (y) and the Gorlin formula (x) was not as good:y=0.77x+0.11, SEE=0.26 cm2,r=0.65,P<0.05. Thus, the continuity equation method using combined continuous wave Doppler and thermodilution technique allows a valid determination of mitral valve area. In patients with mitral stenosis and sinus rhythm, this technique is superior to the noninvasive determination of mitral valve area by the conventional pressure half-time method.

A clinical study was conducted to evaluate the efficacy and safety of percutaneous coronary excimer laser angioplasty in 60 patients with coronary artery disease. Forty-nine patients had stable exertional angina, and 11 patients had unstable angina despite medical therapy. A novel 1.4-mm diameter catheter with 20 quartz fibers of 100-microns diameter each arranged concentrically around a central lumen suitable for a 0.014-in. flexible guide wire was coupled to an excimer laser. A commercial excimer laser emitting energy at a wavelength of 308 nm with a pulse duration of 60 nsec was used. The laser was operated at 20 Hz. Mean energy transmission was 30 +/- 5 mJ/mm2. In five of the 60 patients, laser angioplasty was not attempted. In 23 patients with laser ablation alone, percent stenosis decreased from 76 +/- 14% before to 27 +/- 17% after ablation and was 34 +/- 15% at the early follow-up angiogram. In 32 patients, additional balloon angioplasty was performed because of vessel closure after laser ablation in 11 and an insufficient qualitative result in 21 patients. Of the 11 patients with unstable angina, one patient died due to vessel closure 3 hours after intervention, and two patients developed a myocardial infarction. In 22 of 47 patients with late follow-up angiography, restenosis within the 6-month follow-up period occurred. Rate of restenosis was higher in patients treated with laser ablation and balloon angioplasty (16 of 28) than in patients treated with laser ablation alone (six of 19). These results suggest that coronary excimer laser angioplasty for ablation of obstructive lesions is feasible and safe in patients with stable angina. However, development of new catheter systems is necessary for an improved success rate.

To verify the efficacy and safety of percutaneous coronary excimer laser angioplasty in patients with coronary artery disease a prospective study was conducted in 60 patients. The application of laser light was possible in 55 of the 60 patients. A novel 1.4-mm diameter catheter with 20 quartz fibers of 100-microns diameter, each arranged concentrically around a central lumen suitable for an 0.014-inch flexible guide wire was used. The light source was a commercial excimer laser emitting energy at a wavelength of 308 nm, with a pulse duration of 60 ns. The laser was operated at 20 Hz; mean energy transmission was 30 +/- 5 mJ/mm2. In 23 of the 55 patients treated with excimer laser energy the qualitative angiographic results were sufficient. In 32 patients additional balloon angioplasty was necessary, either because of an insufficient result or due to vessel closure after laser ablation. In 47 of the 55 patients control angiography was performed within the 6-month follow-up period. Rate of restenosis was higher in patients treated with laser ablation and subsequent balloon angioplasty (16 of 28) than in patients treated with laser ablation alone (6 of 19). Results of the 6-month observation period suggest that 1) coronary excimer laser angioplasty in combination with subsequent balloon angioplasty results in a considerable increase of the restenosis rate; 2) the exclusive use of laser ablation also results in a restenosis rate comparable to balloon angioplasty alone; and 3) the impact of this new method using improved application systems and higher energy transmission has to be determined in further studies.