Combined percutaneous approach for aortic valve implantation in poor vascular access.

Transcatheter aortic valve implantation (TAVI) is a well-established management option for symptomatic patients with severe aortic stenosis. The minimally invasive transfemoral approach is considered to be superior to non-transfemoral accesses; however, its use is often limited by concomitant peripheral artery disease (PAD). Percutaneous transluminal angioplasty with stent implantation (PTA) is a gold-standard therapy for symptomatic PAD. We present 2 cases from our cohort of patients with severe aortic stenosis and PAD previously contraindicated for TAVI because of poor peripheral vascular access. However, the patients were eventually treated either by staged PTA and TAVI through an endothelialized stent or PTA and TAVI though a newly implanted peripheral stent during one procedure. We provide recommendations based on our experience of how to select the optimal patients for such a combined minimally invasive transfemoral approach (Fig. 2, Ref. 9). Keywords: transcatheter valve implantation, peripheral arterial disease, aortic valve disease, percutaneous intervention, atherosclerosis.

[Intravascular ultrasound guided direct stent implantation in the treatment of significant stenosis of the left coronary artery]. / Intravaskulárním ultrazvukem rízená prímá implantace stentu pri lécbe významné stenózy kmene levé vencité tepny.

The authors present the case of a 52-year-old patient with the symptomatology of unstable angina pectoris where they diagnosed a major stenosis of the trunk of the left coronary artery as the only significant lesion in the coronary circulation. The patient was successfully treated by means of an intravascular ultrasound--guided coronary stent implanted into the trunk of the left coronary artery. The authors discuss the possibilities and trends of contemporary catheterization treatment of major coronary affections.

[Transcatheter embolization of a coronary fistula in the treatment of ischemic heart disease]. / Katetrizacní uzáver koronární pístele v lécbe ischemické choroby srdecní.

The authors present the case of a 71-year-old female patient with clinical signs of ischaemic heart disease where they diagnosed a coronary fistula between the ramus interventricularis anterior and the trunk of the pulmonary artery. Because of the marked symptomatology they made a transcatheter embolisation of the fistula by introduction of embolisation spirals which led to the elimination of ischaemic symptomatology. Because of the unusual character, pretentious technical aspects and possible risks this operation is indicated only in adult symptomatic patients.

[Percutaneous transluminal septal myocardial ablation in the treatment of hypertrophic obstructive cardiomyopathy: short-term study]. / Perkutánní transluminální septální myokardiální ablace v lécbe hypertrofické obstrukcní kardiomyopatie: krátkodobé sledování.

In 18 patients with symptomatic hypertrophic obstructive cardiomyopathy 18 procedures involving percutaneous transluminal myocardial ablation were performed. The patients were followed up for three months after the procedure. The mean intraventricular peak gradient declined during the intervention from 51 +/- 26 mm Hg to 11 +/- 12.2 mm Hg (p < 0.001). On average 2.7 +/- 1.1 ml ethanol were administered, as a rule into the first septal branch. The target artery was detected in 13 instances by means of myocardial contrast echocardiography and in five instances by haemodynamic investigation. In one instance the procedure was combined with subsequent balloon angioplasty of the ramus circumflexus. In one patient it was necessary to implant ex post a permanent pacemaker on account of AV bloc grade III. In one instance when myocardial contrast echocardiography was not used) infarsation not only of the basal interventricular septum occurred but also of the posterolateral left ventricular wall. During the three-month follow-up the incidence of stenocardias assessed according to CCS declined from grade 2.6 +/- 0.8 to 0.8 +/- 0.8 (p < 0.0001). Dyspnoea evaluated according to NYHA declined from grade 2.9 +/- 0.5 to 1.4 +/- 0.6 (p < 0.0001). The maximal intraventricular gradient evaluated by Doppler echocardiography declined from 57.2 +/- 42 mm Hg before the procedure to 19.7 +/- 12 mm Hg (p < 0.001). An identical gradient after stimulation with one dose of isosorbide dinitrate spray (1.25 mg) declined from 82.3 +/- 27 mm Hg to 25 +/- 6 mm Hg (p < 0.0001). The diastolic thickness of the IVS in the intervened segment declined from 21.2 +/- 3 mm to 14.7 +/- 2 mm (p < 0.0001). No significant change in the size of the left ventricle was recorded, nor in its ejection fraction and size of the left atrium. One patient died suddenly during the follow up period. Percutaneous transluminal septal myocardial ablation leads during short-term follow-up to a significant weakening of the basal segment of the interventricular septum, a decline of the intraventricular gradient and symptomatology of hypertrophic obstructive cardiomyopathy.

Effects of patch number and dispersal patterns on population dynamics and synchrony.

In this paper, we examine the effects of patch number and different dispersal patterns on dynamics of local populations and on the level of synchrony between them. Local population renewal is governed by the Ricker model and we also consider asymmetrical dispersal as well as the presence of environmental heterogeneity. Our results show that both population dynamics and the level of synchrony differ markedly between two and a larger number of local populations. For two patches different dispersal rules give very versatile dynamics. However, for a larger number of local populations the dynamics are similar irrespective of the dispersal rule. For example, for the parameter values yielding stable or periodic dynamics in a single population, the dynamics do not change when the patches are coupled with dispersal. High intensity of dispersal does not guarantee synchrony between local populations. The level of synchrony depends also on dispersal rule, the number of local populations, and the intrinsic rate of increase. In our study, the effects of density-independent and density-dependent dispersal rules do not show any consistent difference. The results call for caution when drawing general conclusions from models of only two interacting populations and question the applicability of a large number of theoretical papers dealing with two local populations.

Does evolution of iteroparous and semelparous reproduction call for spatially structured systems?

A persistent question in the evolution of life histories is the fitness trade-off between reproducing only once (semelparity) in a lifetime or reproducing repeated times in different seasons (iteroparity). The problem can be formulated into a research agenda by assuming that one reproductive strategy is resident (has already evolved) and by asking whether invasion (evolution) of an alternative reproductive strategy is possible. For a spatially nonstructured system, Bulmer (1994) derived the relationship v + PA < 1 (PA is adult survival; vbS and bS are offspring numbers for iteroparous and semelparous breeding strategies, respectively) at which semelparous population cannot be invaded by an iteroparous mutant. When the inequality is changed to v + PA > 1, invasion of a semelparous mutant is not possible. From the inequalities, it is easy to see that possibilities for evolutionary establishment of a novel reproductive strategy are rather narrow. We extended the evolutionary scenario into a spatially structured system with dispersal linkage among the subunits. In this domain, a rare reproductive strategy can easily invade a population dominated by a resident reproductive strategy. The parameter space enabling invasion is far more generous with spatially structured evolutionary scenarios than in a spatially nonstructured system.

Direct stenting without predilatation: a new approach to coronary intervention.

BACKGROUND: Implantation of coronary stents after predilatation is a standard approach in the treatment of most coronary lesions. Stenting without predilatation could be a possible alternative way of treating a certain subset of patients. OBJECTIVE: To identify a group of patients suitable for this optional method, to evaluate their immediate clinical and angiographic outcomes and to test the feasibility and safety of this new therapeutic concept. METHODS: Ninety selected patients with 91 lesions were treated by implantation of coronary stents without predilatation. RESULTS: The mean duration of this procedure was 12.3 +/- 9.1 min and the fluoroscopic time was 3.6 +/- 2.9 min. The stenoses before and after this procedure were 77 +/- 10 and 5 +/- 9%, respectively. Predilatation, postdilatation or implantation of an additional stent was necessary for seven patients. Primary success rate was 92% with an excellent immediate clinical and angiographic outcome. No major complications occurred during direct stenting. CONCLUSION: Direct stenting is feasible using commercially available stents and could be performed for about 20% of patients for whom coronary intervention is indicated. The proper selection of lesions is of crucial importance. Lesions eligible for direct stenting should be without visible calcifications and on vessels without proximal tortuosity. This procedure proved to be safe and successful in this series of coronary interventions.

[Catheter therapy in patients with stable angina pectoris. Results of 662 coronary angioplasties]. / Katetrizacní lécba nemocných se stabilní anginou pectoris. Výsledky 662 koronárních angioplastik.

Coronary angioplasty supplemented by implantation of a stent has become a standard therapeutic method in patients with stable angina pectoris. The authors analyzed the spectrum of patients indicated for this treatment, its successfulness and complications of catheterizations. In the course of a two-year period the authors implemented 662 catheterizations in 602 patients with stable angina. 58% patients indicated for coronary angioplasty on account of stable angina had a history of myocardial Q infarction, 93% had angina grade II or III according to CCS. Affection of one artery was diagnosed in 56% patients, complete revascularization was achieved in 59% of the operations. The clinical rate of success of catheterization was 97% in stenoses of the coronary arteries and 61% in coronary occlusions. In 57% of the treated lesions a coronary stent was implanted. Serious clinical complications developed in 1% of the interventions, none of the patients died. Catheterization treatment of stable angina is very successful and safe.

["Ambulatory" approach to selective coronary angiography: our results and experience]. / "Ambulantní" prístup k selektivní koronarografii: nase výsledky a zkusenosti.

The authors present a group of their first 110 patients subjected to selective coronarography during an average 7-hours hospitalization period. In selection of patients they respect the criteria ruling out the following approach: age above 70 years, distance of the patients domicile above 80 km or inaccessibility of catheterization laboratory within 45 minutes, serious aortic valve disease, unstable coronary syndromes, insulin treated diabetes mellitus, renal insufficiency, cardiac insufficiency, grade III or IV, severe left ventricular dysfunction, history of malignant arrhythmia, acute myocardial infarction or cerebrovascular attack during month preceding examination, coronary finding calling for urgent revascularization, complicated course of examination and mental inability of patient. All coronarographies were performed by a 4F catheterization instrument, no complications were recorded and readmission to hospital was not called for. An early check-up by telephone was accepted by half the patients. When all the above criteria are respected the authors recommend this procedure as a standard one without the need of hospital admission.

[Catheterization therapy of the left main coronary artery in chronic stenosis of the right coronary artery. What are the limits of interventional cardiology?]. / Katetrizacní lécba stenózy kmene levé vencité tepny pri chronickém uzáveru pravé vencité tepny. Kde jsou hranice intervencní kardiologie?

The authors give an account of a 59-year-old patient with a significant stenosis of the left main coronary artery and occlusion of the right coronary artery, occlusion of the ramus interventricularis anterior after failure of surgical revascularization and with a left ventricular ejection fraction of 20%. The authors performed a successful percutaneous coronary angioplasty of the left main coronary artery with an implantation of a stent. They discuss contemporary possibilities and limitations of catheterization treatment of stenosis of the left main coronary artery.

[Treatment of significant coronary stenoses using stents without preliminary balloon angioplasty: present status, results, perspectives]. / Osetrení významných koronárních stenóz pomocí stentu bez predchozí balonkové angioplastiky: soucasný stav, nase výsledky, perspektivy.

The authors present an account on a group of 57 patients where they tried to treat 58 significant coronary stenoses by means of direct stenting without predilatation. In two patients they were able to implant the stent only after previous dilatation, in one instance postdilatation was necessary because of a residual stenosis of more than 20% and in one instance it was necessary to implant another stent on account of distal dissection. Direct stenting was successful in 93%. At the significance level of p < 0.05 significantly shorter fluoroscopic and total intervention times were achieved as compared with the control group where the standard procedures of stenting after previous balloon angioplasty was used. The authors conclude that direct stenting without previous dilatation is a safe method which can be used with the contemporary instrumental equipment in approximately 20% of carefully selected lesions.

[Retrograde intravenous perfusion--a therapeutic method in trophic defects of the lower extremities. Experience in patients with primary thrombocythemia]. / Retrográdní intravenózní perfuze--metoda lécby trofických defektu dolních koncetin. Zkusenosti u pacientu s primární trombocytémií.

Retrograde intravenous perfusion (RIP), so-called Bier's blockade is a relatively new method of treatment of critical ischaemia of the extremities. It is based on the principle of retrograde, i.e. transvenous perfusion of the capillary circulation during which at the time of artificially discontinued circulation in the extremities a high concentration of effective substances in the target tissues is achieved. In addition to the mentioned critical ischaemia Bier's blockade can be successfully used in the treatment of so-called "diabetic foot". It is also possible to implement by this method a local medicamentously induced block of the sympathetic nerves by administration of Guanethidine. In patients with contraindications of systemic fibrinolytic treatment local thrombolysis can be made in phlebothromboses and acral vascular occlusions. In the treatment of tumours on the extremities, e.g. melanoblastome, it is possible to achieve by local administration of cytostatics comparable results, while the incidence of undesirable effects is smaller. The objective of the present work was to make the professional public familiar with this method. On the example of four patients with trophic defects of the lower extremities which developed as a result of primary thrombocythemia the application of Bier's method was demonstrated.

[Catheterization therapy of thromboembolic arterial occlusions of the lower extremities]. / Katetrizacní lécba trombembolických uzáveru tepen dolních koncetin.

Thromboembolic occlusions of peripheral arteries may threaten the vitality of extremities and sometimes patients life. Till recently the main therapeutic method was Fogarty surgical thromboembolectomy. A less invasive procedure is systemic (intravenous) and local (intraarterial) thrombolysis. All these method have, however, certain disadvantages. A new approach to the treatment for acute and subacute occlusions of peripheral arteries represents catheter thromboembolectomy, which involves the following: a) Aspiration of thromboembolic material--percutaneous thrombembolextraction (PTEE), b) Local infiltration thrombolysis where the catheter penetrates through the occlusion while simultaneously administering a fibrinolytic agent, c) PTA of residual stenosis in case of thrombotic occlusion. A combination of these methods of treatment for thromboembolic occlusions of peripheral arteries is very effective and enables to use a small amount of thrombolytic agent. The thrombosis and the underlying atherosclerotic stenosis are resolved during the same session.

[Early results and complications of percutaneous transluminal coronary angioplasty]. / Nase casné výsledky a komplikace perkutánní transluminální koronární angioplastiky.

The authors summarize the early results of coronary angioplasty in 234 patients, with special emphasis on complications. The follow-up group included 182 men (77.8%) and 52 women (22.2%) with a mean age of 52 (34-74) years. Single-artery involvement prevailed (216 patients, 92.3%); multiple artery involvement was diagnosed in 18 patients (7.7%). Overall, dilatation was performed in 273 stenoses; of this number, 213 procedures were successful (78.0%). The primary success rate in the whole group was 76.9% (180/234). The highest success rates were attained in concentric stenoses (88.8%), the lowest ones in complete occlusions (53.8%). Complications were present in 36 patients (15.3%), of this number 14 patients (5.9%) developed acute arterial occlusion; the complications were less severe in 22 patients (9.4%). Of the 14 patients with acute occlusion, eight (3.5%) developed severe complications. One female patient (0.43%) died, one (0.43%) had emergency surgery, and six (2.6%) developed uncomplicated acute myocardial infarction. Perfusion was restored by multiple dilatation in four patients; arterial occlusion, with good collateral circulation, did not result in myocardial infarction in two. Other complications were less severe and had no sequelae including, most often, arterial spasm (3.4%), large dissection demonstrated by angiography (2.6%), protracted hypotension (0.8%), and ventricular fibrillation in one case (0.43%). The article also considers the factors raising the risk of severe complications of coronary angioplasty, and the potential for their prevention and treatment. Coronary angioplasty, employed in an increasing number of patients with symptomatic stenosing atherosclerosis of the coronary arteries, is an effective method successful in 85-95% of patients. The complication rate, while low, is not absolutely negligible.(ABSTRACT TRUNCATED AT 250 WORDS)

Mission-oriented research for light machinery.

The time of intelligent machines is upon us. But the United States is not actively pursuing this rich field of technological development. This is evidenced by the U.S. trade deficit of $9 billion in this market in 1977. The synergistic approach of Japan, Germany, Russia, and other countries to research, development, and demonstration among government, academic, and industrial groups is paying big dividends in vital U.S. markets. This article outlines a specific solution in terms of a U.S. national research policy for light machinery and robotics.