Patient radiation doses during cardiac catheterization procedures

The objective of the present project was the determination of the dose received by patients during cardiac procedures, such as coronary angiography, percutaneous transluminal coronary angioplasty (PTCA) and stent implantation. Thermoluminescent dosemeters (TLDs), suitably calibrated, were used for the measurement of the dose received at four anatomical locations on the patient's skin. A dose-area product (DAP) meter was also used. The contribution of cinefluorography to the total DAP was higher than that of fluoroscopy. A DAP to effective dose conversion factor equal to 0.183 mSv Gy-1 cm-2 was estimated with the help of a Rando phantom. Thus, the effective dose received by the patients could be assessed. Mean values of effective dose equal to 5.6 mSv, 6.9 mSv, 9.3 mSv, 9.0 mSv and 13.0 mSv were estimated for coronary angiography, PTCA, coronary angiography and ad hoc PTCA, PTCA followed by stent implantation and coronary angiography and ad hoc PTCA followed by stent implantation, respectively.     

A study of patient radiation doses in interventional radiological procedures

Patient radiation doses received during interventional radiological procedures can be significant. To aid in the establishment of reference dose levels, a patient dose survey has been conducted of such procedures. A total of 288 non-coronary procedures (177 classified as diagnostic and 111 as therapeutic) were accrued into the study. For each procedure, the fluoroscopy screening time and the fluoroscopic and digital radiographic dose-area products were recorded in a computer database. For example, median dose-area product values (due to fluoroscopy and digital radiography combined) of 24.2, 27.9, 69.6 and 74.7 Gy cm2 were obtained for nephrostomy, biliary stent removal/insertion, cerebral angiography and percutaneous transhepatic cholangiography procedures. While the effective dose is not an accurate measure of patient risk, it is convenient for comparing the radiological risks associated with various procedures. Effective doses were estimated from the total dose-area products. The respective median estimated effective dose values for the four procedures noted above were 3.9, 4.5, 7.0 and 12.0 mSv. While an infrequently performed procedure at this institution (n = 4 during this survey), the transjugular intrahepatic portosystemic shunt (TIPS) procedure had the greatest median dose-area product and effective dose values: 347 Gy cm2 and 55.5 mSv, respectively. Excluding the extreme case of TIPS, it was found that among commonly-performed procedures, those that are categorized as therapeutic do not necessarily present a statistically significant greater radiation risk than those which are diagnostic. Comparisons between dose-area product values obtained from this study are made with data from other interventional radiology patient dose surveys and reasons for some differences noted are discussed.     

Preliminary reference levels in interventional cardiology

This article describes the European DIMOND approach to defining reference levels (RLs) for radiation doses delivered to patients during two types of invasive cardiology procedures, namely coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA). Representative centres of six European countries recorded patients' doses in terms of dose-area product (DAP), fluoroscopy time and number of radiographic exposures, using X-ray equipment that has been subject to constancy testing. In addition, a DAP trigger level for cardiac procedures which should alert the operator to possible skin injury, was set to 300 Gyxcm2. The estimation of maximum skin dose was recommended in the event that a DAP trigger level was likely to be exceeded. The proposed RLs for CA and PTCA were for DAP 45 Gyxcm2 and 75 Gyxcm2, for fluoroscopy time 7.5 min and 17 min and for number of frames 1250 and 1300, respectively. The proposed RLs should be considered as a first approach to help in the optimisation of these procedures. More studies are required to establish certain "tolerances" from the proposed levels taking into account the complexity of the procedure and the patient's size.     

Patient doses in hysterosalpingography

The results of a survey of doses imparted on 41 patients undergoing hysterosalpingography is presented. Dosimetric evaluations were carried out by measuring both the dose-area product using a transmission ionization type chamber, and the entrance surface dose using thermoluminiscent dosimeters. As a result, a local reference dose value was obtained for this examination. Correlations between the dose-area product and the entrance surface dose data were analysed and compared in order to find the most appropriate dosimetric procedure. The median dose-area product obtained was 713 cGy cm2 (range 247 cGy cm2-1623 cGy cm2). Ovarian doses were also calculated, and a median value of 4.6 mGy was obtained for the whole examination. Effective doses were estimated with a median value of 3.1 mSv, and a range of 1.0 mSv-8.1 mSv.     

Radiofrequency thermal balloon coronary angioplasty: a new device for successful percutaneous transluminal coronary angioplasty

OBJECTIVES: The purpose of this study was to evaluate the effects of thermal balloon percutaneous transluminal coronary angioplasty using radiofrequency energy in the treatment of patients with failed coronary angioplasty and complex lesions. In addition, we evaluated restenosis after radiofrequency thermal balloon applications. BACKGROUND: The efficacy of coronary angioplasty is limited by the relatively low success rate in complex lesions and the high frequency of restenosis. Few reports have studied the combined effects of pressure and laser thermal energy. This study describes a new device for coronary angioplasty using radiofrequency thermal energy. METHODS: Thirty-two patients with failed conventional coronary angioplasty or complex lesions were treated with radiofrequency thermal balloon coronary angioplasty. Radiofrequency energy was delivered up to 11 times in exposures ranging from 30 to 60 s in duration. This combined effect allowed the vascular wall to be heated to temperatures ranging from 60 to 70 degrees C. Follow-up coronary angiography was performed, on average, 6 months after the procedure. RESULTS: Successful radiofrequency coronary angioplasty was achieved in 28 (82%) of 34 lesions. There was one abrupt coronary artery occlusion (3%) and no death, perforation or dissection. Angiographic restenosis occurred in 14 (56%) of 25 lesions. CONCLUSIONS: In patients with failed coronary angioplasty and difficult complex lesions, radiofrequency coronary angioplasty could potentially improve angioplasty success rates and may have important implications for bailout cases with abrupt occlusion. However, restenosis remains a significant problem.     

Mycotic aneurysm of the left coronary artery

We report a 24-year-old man with mitral valve endocarditis complicated by acute myocardial infarction due to coronary embolism. Percutaneous transluminal coronary angioplasty and subsequent mitral valve replacement were performed. Postoperative coronary angiography revealed formation of a mycotic aneurysm of the left anterior descending coronary artery at the site of balloon inflation. The patient then underwent successful resection of the aneurysm with coronary artery bypass grafting.     

Effect on coronary artery anatomy of radiofrequency catheter ablation of atrial insertion sites of accessory pathways

OBJECTIVES: The purpose of this study was to analyze the effects of radiofrequency catheter ablation of the atrial insertion site of accessory pathways on the angiographic appearance of coronary arteries. BACKGROUND: Radiofrequency catheter ablation of accessory pathways requires the application of energy to the endocardial surface of the atrioventricular groove adjacent to the major epicardial coronary arteries. A systematic analysis of the effect of radiofrequency ablation on coronary arteries has not previously been demonstrated. METHODS: Seventy consecutive patients with 76 accessory pathways (7 right free wall, 44 left free wall, 12 posteroseptal, 8 anteroseptal and 5 midseptal) were studied. Quantitative coronary angiography was performed before, immediately after and a mean of 69 +/- 42 days after radiofrequency catheter ablation. RESULTS: Coronary artery diameter adjacent to the ablating electrode was 2.6 +/- 0.9 mm before ablation, 2.7 +/- 0.9 mm immediately after ablation and 2.7 +/- 1.0 mm at the time of follow-up study. Angiographic findings were unchanged from baseline in 69 of 70 patients immediately after ablation and in all 70 patients at the time of follow-up study. CONCLUSIONS: Radiofrequency catheter ablation of the atrial insertion site of accessory pathways does not result in short-term angiographic changes in coronary artery anatomy.     

Damage to the circumflex coronary artery during mitral valve repair with sliding leaflet technique

We report a case of damage to the circumflex coronary artery during mitral valve repair using sliding leaflet technique in a patient with a posterior mitral leaflet prolapse and coronary artery disease who underwent mitral valve reconstruction using Carpentier's technique and coronary artery bypass grafting. This case underscores the risk of circumflex coronary artery injury during mitral valve reconstruction, especially in patients with left coronary dominance or codominance, and therefore emphasizes the importance of knowing the coronary artery anatomy preoperatively. The use of intraoperative transesophageal echocardiography is mandatory for the evaluation of mitral valvuloplasty.     

Dose reduction in a paediatric X-ray department following optimization of radiographic technique

A survey of radiation doses to children from diagnostic radiography has been carried out in a dedicated paediatric X-ray room. Entrance surface dose (ESD) and dose-area product (DAP) per radiograph were simultaneously measured with thermoluminescent dosemeters (TLDs) and a DAP meter to provide mean dose values for separate age ranges. Results of ESD and DAP were lower than the mean values from other UK studies for all ages and radiographs, except for the infant pelvis AP radiograph. Comparison of ESD and radiographic technique with CEC quality criteria highlighted a need for reduction of dose to infants and implied an increase in tube filtration might overcome the limitations of the room's three-phase, 12-pulse generator, allowing higher tube potentials to be used on infants. Additional tube filtration of 3 mmA1 was installed following assessment of dose reduction and image quality with test objects and phantoms, and confirmation from the paediatric radiologist that clinical image quality was not-significantly altered. The tube potential was increased from 50 to 56 kVp for the infant pelvis AP radiograph. The resulting ESD and effective dose fell by 51% and 38%, respectively. The CEC quality criteria have proved useful as a benchmark against which technique in X-ray departments can be compared, and as such are a useful tool for optimizing radiographic technique and reducing patient dose.     

Catheter ablation for the common type of atrioventricular nodal reentrant tachycardia

Radiofrequency (RF) catheter ablation of the slow AV nodal pathway was attempted in 34 patients with common type of AV nodal reentrant tachycardia (AVNRT). Radiofrequency energy of 18-32 watts was applied for 30-60 seconds at sites exhibiting atrial-slow pathway potentials or slow potentials. These potentials were recorded at the mid or posterior septum, anterior to the coronary sinus ostium. A mean of two radiofrequency applications successfully eliminated AVNRT in all patients. The incidence of junctional ectopy was significantly higher during 34 effective applications of radiofrequency energy than during 36 ineffective applications (100% versus 17%). Thus, the recording of atrial-slow pathway potentials or slow potentials, and the development of junctional ectopy can be used as a marker for successful ablation. Slow AV nodal conduction was eliminated in 22 patients and persisted without inducible AVNRT in 12. None of the patients had recurrences of AVNRT over a mean follow-up interval of 12 months, and all had preserved AV conduction. Long-term follow-up studies with an electrophysiological method confirmed that the ablation was effective. Transient AV block was observed in only 1 patient, and no major complications were noted. Thus, radiofrequency catheter ablation of the slow AV nodal pathway is highly effective and safe, with a low rate of complication, for the treatment of common type of AVNRT.     

Comparison of immediate hemodynamic response to closed mitral commissurotomy, single-balloon, and double-balloon mitral valvuloplasty in rheumatic mitral stenosis

The hemodynamic response to closed mitral commissurotomy, single-balloon, and double-balloon mitral valvuloplasty was compared using 20 patients in each group. All patients had symptomatic rheumatic mitral stenosis with a mitral valve area < 1 cm2, without any left atrial clot, mitral valve calcification, or mitral regurgitation. There was a significant improvement in hemodynamics following intervention in all three groups. The mean pulmonary artery pressure decreased from 49.1 +/- 17.5 to 28.6 +/- 8.3 mm Hg (p < 0.001), 48.8 +/- 12.3 to 34.0 +/- 13.9 mm Hg (p < 0.001), and 46.7 +/- 18.0 to 26.3 +/- 13.7 mm Hg (p < 0.001) in the closed mitral commissurotomy, single-balloon, and double-balloon mitral valvuloplasty groups, respectively. The mitral valve area increased from 0.62 +/- 0.27 to 1.5 +/- 0.5 cm2 (p < 0.001), 0.68 +/- 0.24 to 1.5 +/- 0.4 cm2 (p < 0.001), and 0.68 +/- 0.25 to 1.9 +/- 0.8 cm2 (p < 0.001) in the closed mitral commissurotomy, single-balloon, and double-balloon mitral valvuloplasty groups, respectively. The increase in the mitral valve area was maximum in the group with double-balloon mitral valvuloplasty. In the closed mitral commissurotomy group there was a significant rise in left ventricular end-diastolic pressure, from 6.8 +/- 3.9 to 9.3 +/- 3.1 mm Hg (p < 0.001), but this remained unchanged in the single-balloon and double-balloon mitral valvuloplasty groups. Our study shows that single-balloon and double-balloon mitral valvuloplasty are comparable to closed mitral commissurotomy in the immediate hemodynamic response, with a larger valve area in the double-balloon mitral valvuloplasty group.     

Follow-up of radiofrequency catheter ablation in children: results in 100 consecutive patients

OBJECTIVES: The purpose of this study was to determine the outcome of a group of closely followed-up pediatric patients who had undergone radiofrequency ablation for cardiac arrhythmias. BACKGROUND: Although radiofrequency ablation in children has been shown to be effective and safe in the short term, results of longer term follow-up of these children must be considered when determining the place of radiofrequency ablation in the management of pediatric arrhythmias. METHODS: One hundred children aged 2 months to 17 years underwent a total of 119 radiofrequency ablation procedures for cure of tachycardia. Follow-up clinical data, electrocardiograms and 24-h Holter monitors were obtained and analyzed. RESULTS: All patients were alive, and none were lost to follow-up after a mean follow-up of 21.5 months (range 6 to 50). Success at last follow-up included accessory pathways in 66 (89%) of 74 patients, atrioventricular (AV) node reentry in 15 (88%) of 17, intraatrial reentry in 2 (67%) of 3, atrial flutter in 3 (100%) of 3, atrial ectopic tachycardia in 2 (67%) of 3, junctional ectopic tachycardia in 1 (100%) of 1 and ventricular tachycardia in 2 (100%) of 2 (overall success, 90 [90%] of 100). All recurrences were observed within 6 months of ablation. Major and minor complications (7%) included chest burn (one patient), foot microembolus (two patients), hematoma without pulse loss (four patients), femoral arteriovenous fistula requiring repair (one patient) and transient Mobitz I AV block (one patient). Immediate success, recurrence and complication rates were similar in the > or = 12-year old versus the < 12-year old group. Echocardiograms, available in 109 (92%) of 119 patients, showed possible procedure-related abnormalities in 2 (mitral regurgitation in 1, tricuspid regurgitation in 1, both mild), with no aortic insufficiency after 30 left-sided ablations performed by the retrograde approach. Follow-up Holter monitors, available in 77 (77%) of 100 patients, showed possible procedure-related abnormalities in 5 (frequent atrial ectopic tachycardia in 2, atrial flutter in 1, accelerated ventricular rhythm in 2). There were no early or late deaths. CONCLUSIONS: In children, the risks of radiofrequency ablation are low at follow-up evaluation. Longer-term follow-up of children undergoing radiofrequency ablation will be necessary to determine whether coronary abnormalities or serious new arrhythmias will develop.     

In vivo radiofrequency thermal balloon angioplasty of porcine coronary arteries: histologic effects and safety

The purpose of this study was to assess the safety and histologic effects of radiofrequency thermal balloon angioplasty in the coronary vasculature of normal pigs. Radiofrequency thermal balloon angioplasty was performed in 30 coronary arteries of 16 nonatherosclerotic pigs. Heated inflations were performed at either 50 degrees, 60 degrees, or 70 degrees C for 30 or 60 seconds, and were compared with five nonheated inflations in five additional arteries. All balloon inflations were performed at 2 atm pressure with a balloon/vessel diameter ratio of 1.2 to 1. Heart rate, arterial pressure, and left ventricular pressure were monitored continuously for each animal. A 12-lead ECG, coronary angiography, and two-dimensional transthoracic echocardiography were performed before and 1 hour after each balloon inflation. Each animal was subsequently put to death for postmortem cardiac examination. Heated inflations were well tolerated in 28 of the 30 arteries without significant adverse effects. During one inflation, ventricular fibrillation occurred because of prolonged ischemia from an occlusive guiding catheter. In another artery, a heated inflation resulted in a dissection with a transient decrease in distal coronary flow. Histologic examination revealed a significant increase in wall thinning and elastic fiber straightening with heating at 70 degrees C for both 30 and 60 seconds, and a significant increase in intracoronary thrombus with heating at 70 degrees C for 60 seconds. Depth of periarterial myocardial heat necrosis paralleled the increase in temperature, with an average depth of 166 microns at 50 degrees C, 312 microns at 60 degrees C, and 1031 microns at 70 degrees C. In vivo, radiofrequency coronary angioplasty can be performed relatively safely without significant electrical, hemodynamic, or ischemic changes beyond those seen with conventional nonthermal angioplasty. The extent of heat-induced vessel wall thinning, elastic tissue straightening, intracoronary thrombus formation, and periarterial myocardial necrosis are all related to balloon temperature or duration of heating.     

The emerging role of MIF in septic shock and infection

A case of successful patch angioplasty for the right coronary artery (RCA) orifice dissection following selective coronary perfusion is reported. A 56-year-old woman who had mitral restenosis, aortic stenosis, and atrial fibrillation with bradycardia-tachycardia syndrome was referred to our hospital for operation. The operation, which contained aortic valve replacement and mitral commissurotomy, was performed with hypothermic cardiopulmonary bypass and crystalloid cardioplegic arrest. The ascending aorta was opened, and selective coronary perfusion was performed. The right coronary cannula was difficult to insert and dislodged several times. At the second infusion of the cardioplegic solution, the right coronary orifice and ascending aortic wall was dissected. The dissection extended to the proximal RCA. The aortotomy was extended into the RCA beyond its orifice. The Xenomedica pericardial patch was used to enlarge the diameter of the RCA with closing the dissected cavity. Then the patch was brought onto the side of the aorta and the aortotomy was closed in the usual manner. Post operative coronary angiography revealed widely patent RCA orifice and good runoff. Two years after operation the patient is free of angina with unlimited physical activity.     

A comparison of patient dose for examinations of the upper gastrointestinal tract at 11 conventional and digital X-ray units in The Netherlands

The objective of this study was to derive the effective dose to patients from examinations of the upper gastrointestinal (GI) tract at 11 X-ray units in 10 Dutch hospitals. Entrance dose and entrance dose rate were measured at the surface of a homogeneous PMMA phantom and at the entrance surface of the image intensifier. Dose-area products (DAPs) were assessed during examinations of patients. The patients (334 females and 256 males) ages were 18-95 years (average 52 years). Effective dose was assessed from DAP using Monte Carlo computer calculations for male and female mathematical anthropomorphic phantoms. The DAPs measured during the survey showed substantial variations, i.e. an overall average value of 21 Gy cm2 and a range of average DAP per X-ray unit varying from 7 to 56 Gy cm2. Variations in the number of images (8-28) and the fluoroscopy time (1.7 min-7.0 min) were also large. A DAP to effective dose conversion factor of 0.32 mSv Gy cm-2 was derived for upper GI studies. The dose survey yielded an overall average effective dose of 6.7 mSv. At one location an examination involving as many as 28 projections was performed, whilst maintaining a DAP well below 15 Gy cm2 and an effective dose below 6 mSv. This was achieved using modern equipment (i.e. high frequency generator, digital spot films) with 0.2 mm additional copper filtration and a relatively high tube voltage. For examinations of the upper GI tract, the application of a reference value of 30 Gy cm2 for the DAP will ensure that, in general, the effective dose to individual patients will not exceed 15 mSv.     

Assessment of accuracy of the Doppler pressure half-time method in the estimation of the mitral valve area immediately after balloon mitral valvuloplasty

AIM: The reliability of Doppler echocardiography in determining the mitral valve area after balloon mitral valvuloplasty has been questioned, as discrepancies were noted between measurements obtained by the pressure half-time method and those derived haemodynamically, immediately following completion of the procedure. Recent investigations, however, have indicated that these discrepancies may be attributable to the over-estimation of the mitral valve area by haemodynamic measurements, caused by the presence of the iatrogenic atrial septal defect complicating transseptal catheterization. The aim of the present study was to further test this hypothesis. METHODS AND RESULTS: Measurements of the mitral valve area by the Doppler pressure half-time method and the Gorlin formula were obtained and compared in 238 consecutive patients before and immediately after retrograde non-transseptal balloon mitral valvuloplasty, which does not involve puncture and/or dilatation of the inter-atrial septum. No significant difference was found between Doppler- and Gorlin-derived measurements, neither before (1.04 +/- 0.23 vs 1.03 +/- 0.23 cm2, P = ns) nor immediately after (2.14 +/- 0.47 vs 2.12 +/- 0.49 cm2, P = ns) valvuloplasty. Linear regression analysis demonstrated a high degree of correlation between Doppler and Gorlin measurements before (r = 0.778) and after (r = 0.886) the procedure. Good agreement was confirmed by the Bland-Altman method. CONCLUSION: Doppler echocardiography yields accurate measurements of the mitral valve area immediately after retrograde non-transseptal balloon mitral valvuloplasty. This finding supports the hypothesis that the creation of an iatrogenic atrial septal defect during transseptal catheterization may contribute to the poor agreement between Doppler and Gorlin data after balloon mitral valvuloplasty.     

Randomized comparison of anatomic and electrogram mapping approaches to ablation of the slow pathway of atrioventricular node reentrant tachycardia

OBJECTIVES: The purpose of this study was to prospectively compare in random fashion an anatomic and an electrogram mapping approach for ablation of the slow pathway of atrioventricular (AV) node reentrant tachycardia. BACKGROUND: Ablation of the slow pathway in patients with AV node reentrant tachycardia can be performed by using either an anatomic or an electrogram mapping approach to identify target sites for ablation. These two approaches have never been compared prospectively. METHODS: Fifty consecutive patients with typical AV node reentrant tachycardia were randomly assigned to undergo either an anatomic or an electrogram mapping approach for ablation of the slow AV node pathway. In 25 patients randomly assigned to the anatomic approach, sequential radiofrequency energy applications were delivered along the tricuspid annulus from the level of the coronary sinus ostium to the His bundle position. In 25 patients assigned to the electrogram mapping approach, target sites along the posteromedial tricuspid annulus near the coronary sinus ostium were sought where there was a multicomponent atrial electrogram or evidence of a possible slow pathway potential. If the initial approach was ineffective after 12 radiofrequency energy applications, the alternative approach was then used. RESULTS: The anatomic approach was effective in 21 (84%) of 25 patients, and the electrogram mapping approach was effective in all 25 patients (100%) randomly assigned to this technique (p = 0.1). The four patients with an ineffective anatomic approach had a successful outcome with the electrogram mapping approach. On the basis of intention to treat analysis, there were no significant differences between the electrogram mapping approach and the anatomic approach with respect to the time required for ablation (28 +/- 21 and 31 +/- 31 min, respectively, mean +/- SD, p = 0.7) duration of fluoroscopic exposure (27 +/- 20 and 27 +/- 18 min, respectively, p = 0.9) or mean number of radiofrequency applications delivered (6.3 +/- 3.9 vs. 7.2 +/- 8.0, p = 0.6). With both the anatomic and electrogram mapping approaches, the atrial electrogram duration and number of peaks in the atrial electrogram were significantly greater at successful target sites than at unsuccessful target sites. CONCLUSIONS: The anatomic and electrogram mapping approaches for ablation of the slow AV nodal pathway are comparable in efficacy and duration. If the anatomic approach is initially attempted and fails, the electrogram mapping approach may be successful at sites outside the areas targeted in the anatomic approach. With both the anatomic and electrogram mapping approaches, there are significant differences in the atrial electrogram configuration between successful and unsuccessful target sites.     

Allyl sulfides from garlic suppress the in vitro proliferation of human A549 lung tumor cells

This study was designed to evaluate the alterations in doppler derived coronary blood flow velocities and flow reserve following rotational ablation. Changes in doppler derived coronary blood flow velocity variables have been valuable in assessing the physiological outcome following coronary balloon angioplasty. Rotational ablation's mechanism of plaque removal could alter distal vascular bed characteristics, and, as a result, intracoronary blood flow velocities and the coronary flow reserve. A 12-MHz doppler guidewire recorded intracoronary phasic velocities and coronary flow reserve (as assessed by the hyperemic response to adenosine [12-18 mcg intracoronary]) in 28 patients, before and after rotational ablation of 30 lesions. Adjunctive balloon angioplasty was performed in 27 of 28 patients (96%). Rotational ablation and adjunctive balloon angioplasty successfully reduced the lesion diameter (87 +/- 9% to 14 +/- 11%; P < 0.001). A significant increase in the mean distal average peak velocity (25 +/- 13 cm/sec, before; 47 +/- 22 cm/sec, after; P < 0.001), and decrease in the proximal to distal average peak velocity ratio, (2.1 +/- 1.3; to 1.2 +/- 0.4; P = 0.002) was recorded. The mean distal diastolic to systolic velocity ratio (before, 1.4 +/- 0.7; after, 1.6 +/- 0.8; P = 0.44) and the coronary flow reserve (before, 1.6 +/- 0.6; after, 1.5 +/- 0.5; P = 0.34) did not increase despite increases in distal velocities, following successful intervention. Doppler derived distal coronary blood flow velocities increased following rotational ablation and adjunctive balloon angioplasty, with resolution of transstenotic velocity gradient. Changes in distal phasic velocity pattern and coronary flow reserve, immediately after the intervention, were not useful in the assessment of the functional outcome and may be related to abnormalities in distal vascular bed vasoreactivity produced by rotational ablation.     

Motor programming of response force and movement direction

The aim of this study was to assess the results of mitral valvuloplasty for chronic asymptomatic or paucisymptomatic mitral regurgitation. Of 584 patients operated for chronic mitral regurgitation between January 1989 and December 1994, 175 were in NYHA Classes I and II and made up the study population. All had chronic grade 3 or 4/4 mitral regurgitation suitable for mitral valvuloplasty. The average follow-up was 34.3 months. Mitral valvuloplasty was performed in 174 patients, the other patient requiring mitral valve replacement. Three patients died (1.7%) and the actuarial 5 year survival was 98.2 +/- 1.0%. The probability of absence of reoperation and absence of thrombo-embolic complications at 5 years were 97 +/- 0.8% and 96.3 +/- 1.7% respectively. The residual regurgitation at Doppler echocardiography was minimal or absent in 94% of patients at the last follow-up control. The mean end-systolic and end-diastolic left ventricular dimensions decreased from 40.0 +/- 6.8 mm and 64.8 +/- 7.0 mm before surgery to 34.6 +/- 6.7 mm (p < 0.001) and 52.7 +/- 7.4 mm (p < 0.001) at the last control. The authors conclude that conservative mitral valve surgery for NYHA Classes I and II patients with chronic mitral regurgitation is feasible with a low risk and is associated with a significant reduction in ventricular volumes and stability of valvular continence at medium-term. When performed by teams trained in techniques of mitral valvuloplasty, these results suggest that surgery should be performed early.     

Microleakage of tooth-colored restorations with a beveled gingival margin

Restenosis remains a major limitation of coronary angioplasty in spite of major advances in techniques and technology. Recent studies have demonstrated that ionizing radiation may limit the degree of this problem. Gamma radiation has been shown to be effective in reducing in stent restenosis in humans, and beta radiation following encouraging results in animals has been shown to be feasible in humans. The objective of this study was to assess the feasibility of a 5 F non-centered catheter to deliver beta radiation emitting seeds to the lesion site post angioplasty and its effect on restenosis. Following successful angioplasty, patients were randomized to treatment with 12, 14 or 16 Gy at the angioplasty site. This was delivered with a 5 F non-centered catheter. Twelve beta radiation emitting seeds (90Sr/Y) were delivered to an area 3 cm in length to cover the angioplasty site. Angiographic follow-up was performed at 6 months. Baseline and follow-up angiograms were performed by blinded investigators at a core laboratory. This interim report comprises the first 35 patients to complete 6-month angiographic follow-up. There were no major radiation incidents. Four patients had evidence of angiographic restenosis. The MLD (mm) and percent stenosis were 0.77 +/- 0.27/72.5 +/- 8.6 pre angioplasty, 2.08 +/- 0.4/25.7 +/- 9.8 post angioplasty and radiation and 2.05 +/- 0.59/25.7 +/- 19.8 at follow-up respectively. CONCLUSION: Beta radiation can be feasibly and safely delivered post coronary angioplasty with a very encouraging reduction of restenosis.