Intravascular ultrasound imaging after excimer laser angioplasty

To help elucidate the mechanism of excimer laser coronary angioplasty (ELCA), intra-vascular ultrasound (IVUS) imaging was performed in 19 of 29 patients who were treated with ELCA. The results were compared with a non-randomized control group of 18 patients who had IVUS studies both before and after PTCA alone. After ELCA alone, lumen diameter (1.9 × 1.7 mm) and lumen cross-sectional area (CSA) (2.9 mm²) by IVUS were not significantly different from baseline values in the patients before PTCA alone (2.1 × 1.8 mm, 3.2 mm²). After balloon dilatation in the laser treated group, lumen diameter (2.5 × 2.1 mm) and lumen CSA (4.9 mm²) were significantly greater than those post ELCA alone. However, there was no difference in lumen CSA or atheroma CSA in the group treated with excimer laser plus balloon dilatation vs. these measurements in the group treated with PTCA alone. ELCA does not ablate a large amount of atheroma (9% reduction) but creates a pathway to permit easier passage of a PTCA balloon. These quantitative and morphologic results may help explain why the restenosis rate with ELCA is similar to PTCA alone. © 1994 Wiley-Liss,Inc..     

Radiofrequency Delivery Through a Cooled Catheter Tip Allows the Creation of Larger Endomyocardial Lesions in the Ovine Heart

RF Lesions From Cooled Electrode. Introduction: The delivery of radiofrequency (RF) energy through conventional catheter electrodes is often associated with coagulation necrosis at the tissue-electrode interface, with resultant impedance rise and limited lesion size. This study was performed to examine the effects of catheter tip cooling during RF delivery, to test the hypothesis that such cooling would decrease the likelihood of impedance rise and allow the creation of larger endomyocardial lesions. Methods and Results: The experiments were performed in eight open chest, anesthetized sheep. RF lesions were created within both ventricular chambers of each animal through a catheter tip that could he cooled with a saline perfusate. Assignment of cooled versus non-cooled RF delivery to either ventricle was alternated from one animal to the next. In each set of experiments, lesion volumes relative to the mode of RF delivery were compared. The mean power delivered via the cooled electrode (22.04 ± 4.51 W) was significantly higher than that delivered via the noncooled electrode (6.10 ± 2.47 W; P < 0.001). The mean duration of RF delivery was 42.7 ± 11.2 sec for noncooled lesions versus 49.2 ± 6.8 sec for cooled lesions (P < 0.01). Mean lesion volume was 436.07 ± 177.00 mm³ for noncooled RF delivery versus 1247.78 ± 520.51 mm³ for cooled RF delivery (P < 0.001). This significantly larger lesion size with cooled RF delivery was associated with no instance of impedance rise in 27 attempts versus 11 impedance rises in 28 attempts with noncooled RF (P < 0.001). Conclusions: Delivery of RF energy through a cooled catheter tip allows the creation of larger endomyocardial lesions by limiting the occurrence of impedance rise despite the delivery of greater energy. These observations suggest that, under certain conditions, resistive tissue heating at a distance from the site of current delivery may play an important role in RF ablation therapy.     

Sex-Related Differences of Coronary Atherosclerosis Regression Following Maximally Intensive Statin Therapy: Insights From SATURN

ObjectivesThe study sought to explore sex-related differences in coronary atheroma regression following high-intensity statin therapy.BackgroundGuidelines now recommend high-intensity statins in all individuals with atherosclerotic cardiovascular disease.MethodsSATURN (Study of Coronary Atheroma by Intravascular Ultrasound: Effect of Rosuvastatin Versus Atorvastatin) employed serial intravascular ultrasound measures of coronary atheroma volume in patients treated with rosuvastatin 40 mg or atorvastatin 80 mg for 24 months. The treatment groups did not differ significantly in change from baseline of percent atheroma volume (PAV) or total atheroma volume (TAV) on intravascular ultrasound, nor in safety or clinical outcomes.ResultsCompared with men (n = 765), women (n = 274) were older (p < 0.001) and more likely to have hypertension (p < 0.001), diabetes (p = 0.002), and higher low-density lipoprotein cholesterol (LDL-C) (p = 0.01), high-density lipoprotein cholesterol (p < 0.001), and C-reactive protein (CRP) (p = 0.004) levels. At follow-up, women had higher high-density lipoprotein cholesterol (p < 0.001) and CRP (p < 0.001), but similar LDL-C (p = 0.46) levels compared with men. Compared with men, women had lower baseline PAV (34.0 ± 8.0% vs. 37.2 ± 8.2%, p < 0.001) and TAV (122.4 ± 55 mm³ vs. 151.9 ± 63 mm³, p < 0.001), yet demonstrated greater PAV regression (–1.52 ± 0.18% vs. –1.07 ± 0.10%, p = 0.03) and TAV regression (–8.27 ± 0.9 mm³ vs. –6.59 ± 0.50 mm³, p = 0.11) following treatment. Greater PAV regression in women versus men occurred with rosuvastatin (p = 0.004), those with diabetes (p = 0.01), stable coronary disease (p = 0.01), higher baseline LDL-C (p = 0.02), and higher CRP (p = 0.04) levels. On multivariable analysis, female sex was independently associated with PAV regression (p = 0.01), and a sex-treatment interaction was found (p = 0.036). For participants with on-treatment LDL-C levels <70 mg/dl, women achieved greater PAV regression (–1.81 ± 0.22% vs. –1.12 ± 0.13%, p = 0.007) and TAV regression (–10.1 ± 1.1 mm³ vs. –7.16 ± 0.65 mm³, p = 0.023) than men, whereas PAV and TAV regression did not differ by sex, with LDL-C levels ≥70 mg/dl.ConclusionsWomen with coronary disease demonstrate greater coronary atheroma regression than men when empirically prescribed guideline-driven potent statin therapy. This benefit appears in the setting of lower on-treatment LDL-C levels. (CRESTOR Athero Imaging Head to Head IVUS Study [SATURN]; NCT000620542)     

T-lymphocytes expressing CC chemokine receptor-5 are increased in frail older adults

OBJECTIVES: To evaluate the frequencies of T‐lymphocytes expressing CC chemokine receptor‐5 (CCR5⁺ T‐cells) and their relationship with frailty in older adults. DESIGN: Case‐control study with an age‐, race‐, and sex‐matched design. SETTING: General Clinical Research Center. PARTICIPANTS: Community‐dwelling adults aged 72 and older from Baltimore, Maryland. METHODS: Frailty was determined using five validated criteria: weakness, slow walking speed, fatigue, low physical activity, and weight loss. Those meeting three or more of these five criteria were defined as frail and those with none as nonfrail. Complete blood counts were performed to obtain peripheral lymphocyte counts using an automated (Coulter) counter. Peripheral blood was collected for surface immunofluorescent staining of CCR5 and other T‐cell markers. RESULTS: Twenty‐six frail and matched nonfrail participants (mean age±standard deviation 83.8±5.3, range 72–94) completed the study. Frail participants had higher CCR5⁺, CCR5⁺CD8⁺, and CCR5⁺CD45RO^? T‐cell counts than matched nonfrail controls (349±160/mm³ vs 194±168/mm³, P=.02; 208±98/mm³ vs 105±62/mm³, P=.02; and 189±149/mm³ vs 52±36/mm³, P=.01; respectively). Furthermore, there was a trend toward graded increase in these T‐cell counts across the frailty scores in frail participants (e.g., CCR5⁺CD8⁺ counts of 123±52/mm³, 248±115/mm³, and 360±215/mm³ for those with frailty scores of 3, 4, and 5, respectively). CONCLUSION: These initial results suggest an expansion of the CCR5⁺ T‐cell subpopulation in frailty. They provide a basis for further characterization of CCR5⁺ T‐cells and their role in frailty, with potential therapeutic implications.     

Coronary artery lumen volume measurement using three-dimensional intravascular ultrasound: Validation of a new technique

Objective: To validate an automated algorithm for the measurement of lumen volumes of coronary arteries. Background: Current intravascular ultrasound systems use absolute measurements of and changes in areas and diameters for the assessment of coronary artery disease. However, the coronary artery is a three-dimensional structure of complex geometry and volume. Methods: We used a comprehensive imaging system designed to reconstruct planar intravascular ultrasound images in three dimensions. This system consisted of a 25 MHz transducer-tipped rigid probe (for in vitro studies) or a 25 MHz transducer-tipped catheter within a 3.9F monorail imaging sheath (for in vivo studies), a motorized catheter pullback device that withdrew the transducer at 0.5 mm/sec, and an image processing computer that stacked 15 image slices/mm of vessel axial length and then performed thresholding-based three-dimensional image rendering and lumen volume measurement. We imaged 13 human coronary vessels (6 RCA, 6 LAD, 1 LCX) in vitro and 16 vessels (8 LAD, 6 RCA, 2 SVG) in vivo. Results: In vitro studies: Lumen volumes derived by three-dimensional intravascular ultrasound were 171 ± 121 mm³ and compared very well with those derived by histology (160 ± 109 mm³, r = 0.97, SEE = 29 mm³, P < 0.001) and with those derived by manual planimetry of planar intravascular ultrasound images (150 ± 106 mm³, r = 0.97, SEE = 30 mm³, P < 0.001). In vivo studies: Lumen volumes derived by three-dimensional intravascular ultrasound were 74 ± 35 mm³ and compared well with those derived by quantitative angiography (52 ± 20 mm³, r = 0.71, SEE = 25 mm³, P < 0.002). Conclusions: Three-dimensional intravascular ultrasound is a new technique that can accurately measure coronary artery lumen volumes. Further technical improvements may help to establish this technique as the new standard for lumen volume measurement. © Wiley-Liss, Inc.     

Comparison of epicardial cryoablation and irrigated radiofrequency ablation in a Swine infarct model

Epicardial Cryoablation in Swine. Introduction: Cryoablation is an alternative to radiofrequency (RF) energy used in some ablation procedures. Its role and effectiveness compared to irrigated RF in epicardial tissue and epicardial substrates is not yet fully established. Methods and Results: Using a swine chronic infarct model, we compared RF lesions produced by an open‐irrigated 3.5 mm tip catheter with those produced by an 8 mm tip cryocatheter in epicardial infarct border zone, epicardial normal tissue, and normal endocardium. In the infarct border zone, cryolesions were larger than RF lesions in maximum diameter (9.3 ± 2.9 mm vs 6.2 ± 2 mm, P < 0.001) and volume (171.7 ± 173.1 mm³ vs 77 ± 53.5 mm³, P = 0.021). In normal epicardial tissue, cryolesions were larger in maximum diameter (11.2 ± 4.3 mm vs 7.7 ± 3.1 mm, P = 0.012), depth (5.8 ± 1.6 mm vs 4.7 ± 1.4 mm, P = 0.034), and volume (274.7 ± 242.2 mm³ vs 112 ± 102.9 mm³, P = 0.002). In normal endocardium, no significant differences were found. Conclusions: Epicardial cryoablation with an 8 mm tip cryocatheter led to larger lesion volume in infarcted myocardium compared to a 3.5 mm irrigated RF catheter. This is likely related to a combination of cryoadherence, more efficient energy delivery with horizontal orientation, and lack of warming by circulating blood. Cryoablation merits further investigation as a modality for treating ventricular tachycardia of epicardial origin in humans. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1016‐1023, September 2012)     

Cardiac Shock Wave Therapy for Chronic Refractory Angina Pectoris. A Prospective Placebo‐Controlled Randomized Trial

Background: Cardiac shock wave therapy (CSWT) delivered to the myocardium increases capillary density and regional myocardial blood flow in animal experiments. In addition, nonenzymatic nitric oxide production and the upregulation of vascular growth factor's mRNA by CSWT have been described. The aim of the study was therefore to test its potential to relieve symptoms in patients with chronic stable angina pectoris. Methods: Twenty‐one patients (mean age 68.2 ± 8.3 years, 19 males) with chronic refractory angina pectoris and evidence of inducible myocardial ischemia during MIBI‐SPECT imaging, were randomized into a treatment (n = 11) and a placebo arm (n = 10). The region of exercise‐induced ischemia was treated with echocardiographic guidance during nine sessions over a period of 3 months. One session of CSWT consisted of 200 shots/spot (9‐‐12 spots/session) with an energy intensity of 0.09 mJ/mm². In the control group acoustic simulation was performed without energy application. Medication was kept unchanged during the whole treatment period. Results: In the treatment group, symptoms improved in 9/11 patients, and the ischemic threshold, determined by cardiopulmonary exercise stress testing, increased from 80 ± 28 to 95 ± 28 W (P= 0.036). In the placebo arm, only 2/10 patients reported an improvement and the ischemic threshold remained unchanged (98 ± 23 to 107 ± 23 W; P= 0.141). The items “physical functioning” (P= 0.043), “general health perception” (P= 0.046), and “vitality” (P= 0.035) of the SF‐36 questionnaire significantly improved in the treatment arm, whereas in the placebo arm, no significant change was noted. Neither arrhythmias, troponin rise nor complications were observed during treatment. Conclusions: This placebo controlled trial shows a significant improvement in symptoms, quality of life parameters and ischemic threshold during exercise in patients with chronic refractory angina pectoris treated with CSWT. Thus, CSWT represents a new option for the treatment of patients with refractory AP.     

Intravascular ultrasound and 3D angle measurements of coronary bifurcations

Objective: To standardize the intravascular ultrasound (IVUS) analysis of coronary bifurcations. Background: Percutaneous treatment of bifurcation lesions is difficult particularly at the side branch ostium. Imaging techniques may improve our understanding of treatment options. There is no established IVUS methodology to assess the bifurcation. The present study aims to develop standards for bifurcation imaging. Methods: Quantitative IVUS analysis and 3D bifurcation angle measurements were performed in 34 patients who were selected from the Washington Hospital Center Database. Patients were included if both left anterior descending (LAD) and first diagonal (DX) pullbacks in the same procedure were done. Angiograms were available in 27 patients to measure the 3D bifurcation angle using specialized software. Pullbacks were analyzed proximal and distal to the bifurcation, and at the bifurcation. Results: Prox_LAD versus Prox_LAD(DX) were similar for vessel area (15.5 ± 4.6 mm² vs. 15.9 ± 4.0 mm², P = 0.19), lumen area (8.3 ± 3.6 mm² vs. 8.6 ± 3.3 mm², P = 0.25), and plaque area (7.2 ± 2.0 mm² vs. 7.3 ± 1.9 mm², P = 0.55). However, Bifurcation_LAD was larger than Bifurcation_DX for vessel area (17.3 ± 4.0 mm² vs. 16.6 ± 3.9 mm², P = 0.0083). The 3D angiographic bifurcation angle was 50° ± 13° (range of 26°–84°), and did not affect the IVUS measurements. IVUS analysis showed that bifurcation lesions did obey Murray's Law, as Prox_LAD lumen area measured 36.7 ± 25.1 mm³ versus Dist_LAD/Dist_DX measured 38.0 ± 29.1 mm³, P = 0.56. Conclusions: Two IVUS pullbacks should be performed for a complete assessment of the bifurcation and comparison with Murray's Law. The proposed IVUS analysis was not influenced by the bifurcation angle. © 2009 Wiley‐Liss, Inc.     

Coronary plaque morphology affects stent deployment: Assessment by intracoronary ultrasound

The purpose of this study was to evaluate the changes in arterial wall morphology induced by coronary stent implantation and the influence of plaque morphology on stent expansion by intravascular ultrasound. Intravascular ultrasound imaging was performed in 25 lesions before and after Palmaz-Schatz stent implantation. In the 25 lesions with ultrasound images before and after stent deployment angiographic percent diameter stenosis decreased from 71% ± 11% to 6% ± 14%. By ultrasound there was a gain in luminal area from 2.0 mm² ± 1.5 mm² to 6.6 mm² ± 2.1 mm² owing to a gain in external elastic membrane area of 2.5 mm² ± 1.7 mm² and reduction of plaque area of 2.1 mm² ± 1.7 mm². Calcified lesions (n = 8) showed significantly less relative luminal gain (218% ± 128% vs. 421% ± 276%, P = .01), and stent expansion was significantly less symmetric (minimal/maximal stent diameter 0.8 ± 0.1 vs. 0.9 ± 0.1, P = .002) as compared to non-calcified lesions (n = 17). The difference in lumen area within the stent between the previously stenotic area and the ends of the stent was significantly larger in calcified lesions as compared to non-calcified lesions (29 ± 28% vs. 8 ± 23%, P = .03). Both vessel stretch and plaque reduction contribute to the luminal gain after coronary stenting. Calcified lesions interfere with optimal stent expansion. © 1996 Wiley-Liss, Inc.     

ECG-gated versus nongated three-dimensional intracoronary ultrasound analysis: Implications for volumetric measurements

The quantitative analysis of a three-dimensional (3-D) intracoronary ultrasound (ICUS) image data set permits a more comprehensive assessment of coronary arterial segments. The 3-D image sets are generally acquired during continuous motorized pullbacks. However, the cyclic changes of vascular dimensions and the cyclic spatial displacement of the ICUS transducer relative to the vessel wall can result in characteristic image artifacts, which may limit the applicability of quantitative automated analysis systems. This limitation may be overcome by an ECG-gated image acquisition. In the present study we acquired in vivo (1) nongated and (2) ECG-gated 3-D ICUS image sets of 15 human atherosclerotic coronary arteries and performed a computer-assisted contour detection of the lumen and total vessel boundaries. Total vessel and lumen volumes measured significantly larger in the nongated versus ECG-gated end-diastolic image sets (753 ± 307 mm³ vs. 705 ± 305 mm³; 411 ± 154 mm³ vs. 388 ± 165 mm³, both: P < 0.05). Both end-diastolic and systolic measurements were available in nine arteries, showing a larger total vessel and lumen volume at systole (664 ± 221 mm³ vs. 686 ± 227 mm³, P = 0.03; 384 ± 164 mm³ vs. 393 ± 170 mm³, P = 0.08). The differences observed may be of particular interest for volumetric ICUS studies, addressing presumably small differences in vessel or lumen dimensions. Cathet. Cardiovasc. Diagn. 43:254–260, 1998. © 1998 Wiley-Liss, Inc.     

IVUS radiofrequency analysis in the evaluation of the polymeric struts of the bioabsorbable everolimus‐eluting device during the bioabsorption process

Background : In the ABSORB study cohort A the changes in the amount of dense calcium and necrotic core have not been reported in comparison to the prestenting phase; this evaluation could be useful to better clarify the bioabsorption process. Aim of this study was therefore to evaluate the dynamic changes in plaque size and plaque tissue composition observed between 6 months and 2 years follow‐up, and to compare these findings to the prestenting phase. Methods : Angiography, intravascular ultrasound and derived parameters (virtual histology, palpography, and echogenicity) were serially assessed postprocedure, at 6 months and at 2 years in 20 patients. In a subset of 8 patients the same measurements were also recorded in the prestenting phase. Results : In the total population a reduction of 18% in the plaque area was observed between 6 month and 2 year follow‐up (7.56 ± 2.32 mm² at 6 months vs. 6.16 ± 2.10 mm² at 2 year follow‐up; P < 0.01). In the subgroup of eight patients who underwent IVUS during the pre‐stenting phase, the plaque area at 2 year follow‐up was not significantly different when compared to the prestenting plaque area (7.29 ± 2.29 mm² at prestenting vs. 7.48 ± 1.45 mm² at 2 year follow‐up, P = NS). Necrotic core area was reduced by 24% between the 6 month and 2 year follow‐up (0.97 ± 0.66 mm² at 6 months vs. 0.74 ± 0.53 mm² at 2 year follow‐up; P = NS), whilst dense calcium was reduced by 14% from 6 month to 2 year follow‐up (0.83 ± 0.50 mm² at 6 months vs 0.72 ± 0.64 mm² at 2 year follow‐up; P = NS). Whilst the necrotic core at 2 years follow‐up was not significantly different when compared to the pre‐stenting phase (0.62 ± 0.42 mm² prestenting vs 1.07 ± 0.56 mm² at 2 year follow‐up; P = NS), the area of dense calcium was significantly higher at follow‐up compared to prestenting (0.35 ± 0.35 mm² pre‐stenting vs. 0.84 ± 0.66 mm² at 2 year follow‐up; P < 0.05). Conclusions : The reduction in the necrotic core component between 6 month and two year follow‐up could be related to a synergistic effect of the bio‐absorption process and the anti‐inflammatory action of everolimus. © 2010 Wiley‐Liss, Inc.     

Temporary arterial stenting: Comparison to permanent stenting and conventional balloon injury in a rabbit carotid artery model

The objective was to assess the arterial wall response to temporary stenting with a removable nitinol stent in comparison with permanent stenting and balloon injury at 28 days in the rabbit carotid artery. Restenosis remains an important limiting factor after the implantation of permanent metallic stents and balloon angioplasty. We have developed a temporary nitinol stent that uses a bolus injection of warmed saline to collapse the stent for percutaneous removal. Vascular changes related to the thermal saline bolus injection required to remove a nitinol implanted stent were assessed in 12 rabbit carotid arteries at 7 and 28 days postinjection. Nitinol stents, inflated to 3.0 mm diameter, were implanted for 3 days (n = 6) and histology and quantitative histomorphometry examined at 28 days. Results were compared with permanently implanted stents (n = 5) and balloon injury (n = 9). Dual bolus injection of 10 ml at 70°C created an acute necrotizing injury and chronic neointimal proliferation, whereas injections of 5 ml at 63°C were minimally injurious. Temporary stenting resulted in the least neointimal proliferation measured by the intima to media ratio (0.22 ± 0.10 vs. 1.59 ± 0.31 for permanent stenting and; 0.49 ± 0.14 for balloon injury; P < 0.001). Temporary stenting maintained a significantly larger lumen than balloon (1.53 ± 0.72 mm² vs. 0.64 ± 0.14 mm²; P < 0.001), which could not be explained by absolute changes in intimal cross sectional area (0.14 ± 0.07 mm² vs. 0.21 ± 0.06 mm² respectively; P = 0.33). Temporary stenting resulted in a relatively larger vessel area within the external elastic lamina than with balloon (2.28 ± 1.06 mm² vs. 1.30 ± 0.18 mm²; P = 0.007). The thermal stent recovery process can create necrotizing vascular injury and neointimal proliferation at higher temperatures and injectate volumes. Stent removal after 3 days using 63°C saline bolus injection results in less neointimal proliferation than with permanent stents or balloon injury. In comparison to balloon injury, temporary stenting also may have a long-lasting beneficial effect on vessel recoil and remodeling, resulting in larger lumen size after stent removal. Cathet. Cardiovasc. Diagn. 41:85–92, 1997. © 1997 Wiley-Liss, Inc.     

Reversal of pulmonary vein remodeling after catheter ablation of atrial fibrillation

Background Pulmonary veins (PV) and the atria undergo electrical and structural remodeling in atrial fibrillation (AF). This study aimed to determine PV and left atrial (LA) reverse remodeling after catheter ablation for AF assessed by chest computed tomography (CT). Methods PV electrophysiologic studies and catheter ablation were performed in 63 patients (68% male; mean ± SD age: 56 ± 10 years) with symptomatic AF (49% paroxysmal, 51% persistent). Chest CT was performed before and 3 months after catheter ablation. Results At baseline, patients with persistent AF had a greater LA volume (91 ± 29 cm³ vs. 66 ± 27 cm3; P = 0.003) and mean PV ostial area (241 ± 43 mm² vs. 212 ± 47 mm²; P = 0.03) than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients (76%) were AF free on or off antiar?rhythmic drugs. There was a significant reduction in LA volume (77 ± 31 cm³ to 70 ± 28 cm³; P < 0.001) and mean PV ostial area (224 ± 48 mm² to 182 ± 43 mm²; P < 0.001). Patients with persistent AF had more reduction in LA volume (11.8 ± 12.8 cm³ vs. 4.0 ± 11.2 cm³; P = 0.04) and PV ostial area (62 mm² vs. 34 mm²; P = 0.04) than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume (r = 0.38, P = 0.03). Conclusions Catheter ablation of AF improves structural remodeling of PV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.     

Progressive vascular remodeling and reduced neointimal formation after placement of a thermoelastic self-expanding nitinol stent in an experimental model

Despite the improvements afforded by intracoronary stenting, restenosis remains a significant problem. The optimal physical properties of a stent have not been defined. We compared the vascular response to a thermoelastic self-expanding nitinol stent with a balloon-expandable tubular slotted stainless steel stent in normal porcine coronary arteries. Twenty-two stents (11 nitinol and 11 tubular slotted) were implanted in 11 miniature swine. The nitinol stents were deployed using the intrinsic thermal properties of the metal, without adjunctive balloon dilation. The tubular slotted stents were implanted using a noncompliant balloon with a mean inflation pressure of 12 atm. Intravascular ultrasound (IVUS) and histology were used to evaluate the vascular response to the stents. The mean cross-sectional area (CSA) of the nitinol stents (mm²) as measured by IVUS increased from 8.13 ± 1.09 at implant to 9.10 ± 0.99 after 28 days (P = 0.038), while the mean CSA of the tubular slotted stents was unchanged (7.84 ± 1.39 mm² vs. 7.10 ± 1.07 mm², P = 0.25). On histology at 3 days, the tubular slotted stents had more inflammatory cells adjacent to the stent wires (5.7 ± 1.5 cells/0.1 mm²) than the nitinol (3.9 ± 1.3 cells/0.1 mm², P = 0.016). The tubular slotted also had increased thrombus thickness (83 ± 85 μ) than the nitinol stents (43 ± 25 μ, P = 0.0014). After 28 days, the vessel injury score was similar for the nitinol (0.6 ± 0.3) and the tubular slotted (0.5 ± 0.1, P = 0.73) designs. The mean neointimal area (0.97 ± 0.46 mm² vs. 1.96 ± 0.34 mm², P = 0.002) and percent area stenosis (15 ± 7 vs. 33 ± 7, P = 0.003) were significantly lower in the nitinol than in the tubular slotted stents, respectively. We conclude that a thermoelastic nitinol stent exerts a more favorable effect on vascular remodeling, with less neointimal formation, than a balloon-expandable design. Progressive intrinsic stent expansion after implant does not appear to stimulate neointimal formation and, therefore, may provide a mechanical solution to prevent in-stent restenosis. Cathet. Cardiovasc. Diagn. 44:193–201, 1998. © 1998 Wiley-Liss, Inc.     

Ablation efficacy and electrical morphology of a novel 18-hole open-irrigated catheter

Ablation Efficacy and Electrical Morphology. Introduction: The 6‐hole open‐irrigated catheter (SHOI) is increasingly used in radiofrequency (RF) ablation of arrhythmias. However, deep transmural lesions are not always achieved, and volume overload caused by irrigated ablation is another problem that should be concerned. The purpose of this study was to analyze and compare the ablation effect and electrical morphology between a novel 18‐hole open‐irrigated catheter (EHOI) and SHOI. Methods and Results: The heart was exposed through a median sternotomy in 12 anesthetized dogs, and the chest cavity was filled with heparinized saline. Bipolar contact pericardial electrograms of both catheters were recorded. Lesions were created under all permutations of the following conditions: RF energy 30 and 40 W for 60 seconds, contact force at 10, 30, and 50 g, electrode orientation horizontal to the tissue, irrigation rate 10 mL/min for EHOI and 17 mL/min for SHOI. The EHOI created deeper lesions than SHOI (5.77 ± 1.37 mm vs 4.98 ± 1.22 mm at power of 30 W, P < 0.05; 7.16 ± 1.15 mm vs 6.02 ± 1.04 mm at power of 40 W, P < 0.01), and there was a trend of larger lesion volume for EHOI (312 ± 141 mm³ vs 259 ± 108 mm³ at power of 30 W, 536 ± 200 mm³ vs 451 ± 180 mm³ at power of 40 W, P > 0.05). No significant difference in electrogram morphology between 2 catheters was detected. Conclusions: The mapping electrograms of EHOI and SHOI were not significantly different. Compared with SHOI, EHOI more effectively produced deeper lesions at a lower rate of irrigation perfusion. (J Cardiovasc Electrophysiol, Vol. 22, pp. 691‐697, June 2011)     

Coronary intravascular lithotripsy and rotational atherectomy for severely calcified stenosis: Results from the ROTA.shock trial

Background

Severely calcified coronary lesions present a particular challenge for percutaneous coronary intervention.

Aims

The aim of this randomized study was to determine whether coronary intravascular lithotripsy (IVL) is non-inferior to rotational atherectomy (RA) regarding minimal stent area (MSA).

Methods

The randomized, prospective non-inferiority ROTA.shock trial enrolled 70 patients between July 2019 and November 2021. Patients were randomly (1:1) assigned to undergo either IVL or RA before percutaneous coronary intervention of severely calcified coronary lesions. Optical coherence tomography was performed at the end of the procedure for primary endpoint analysis.

Results

The primary endpoint MSA was lower but non-inferior after IVL (mean: 6.10 mm², 95% confidence interval [95% CI]: 5.32–6.87 mm²) versus RA (6.60 mm², 95% CI: 5.66–7.54 mm²; difference in MSA: −0.50 mm², 95% CI: −1.52–0.52 mm²; non-inferiority margin: −1.60 mm²). Stent expansion was similar (RA: 0.83 ± 0.10 vs. IVL: 0.82 ± 0.11; p = 0.79). There were no significant differences regarding contrast media consumption (RA: 183.1 ± 68.8 vs. IVL: 163.3 ± 55.0 mL; p = 0.47), radiation dose (RA: 7269 ± 11288 vs. IVL: 5010 ± 4140 cGy cm²; p = 0.68), and procedure time (RA: 79.5 ± 34.5 vs. IVL: 66.0 ± 19.4 min; p = 0.18).

Conclusion

IVL is non-inferior regarding MSA and results in a similar stent expansion in a random comparison with RA. Procedure time, contrast volume, and dose-area product do not differ significantly.     

Comparison of a Saline Irrigated Cooled-Tip Catheter to Large Electrode Catheters with Single and Multiple Temperature Sensors for Creation of Large Radiofrequency Lesions

Background: Several catheter technologies for creating large radiofrequency (RF) lesions are used in clinical practice, but direct comparisons of the pathological lesions created by these technologies are unavailable. The purpose of this study was to compare the safety and efficacy of lesions created by three different large lesion RF ablation technologies. Methods and Results: RF lesions were created in all four chambers of 15 mongrel dogs using 10 mm-tip multiple temperature sensor catheters, 10 mm tip single temperature sensor catheters, and 4 mm cooled-tip catheters. Pathological lesions were bisected, and measured after viability staining. A total of 242 (79 large-tip single sensor, 82 large-tip multiple sensor, and 81 cooled-tip) lesions were created. All atrial lesions were transmural but tended to have larger surface areas with the single thermistor large-tip catheter (73.4 ± 24.8 mm²) compared to either the multithermistor large-tip (60.9 ± 28.3 mm²) or the cooled-tip (61.9 ± 28.5 mm²) catheters (p = 0.07), especially those in the IVC-TA isthmus. Depths and volumes of ventricular lesions created by the multiple-thermistor catheter (5.0 ± 1.5 mm; 260 ± 168 mm³) were smaller than either the single thermistor (5.7 ± 1.5 mm; 428 ± 290 mm³) or cooled-tip (6.1 ± 1.8 mm; 403 ± 217 mm³) catheters (p < 0.05). The difference in the depth and volume of lesions made by large-tip single thermistor and cooled-tip catheters was not significant. Char formation occurred during 11% of ablation with the single thermistor catheter, 6% with multithermistor and 8% of cooled-tip catheter (p = NS). There were no complications of ablation. Conclusions: All three catheters reliably created full thickness atrial lesions. For ventricular lesions, depths and volumes were similar for 10 mm-tip single thermistor and cooled-tip catheters. The multithermistor catheter lesions were smaller due to more precise temperature regulated power control. Safety was similar in all 3 groups.     

Clinical evaluation of a microsample coagulation analyzer,and comparison with existing techniques

A new microsample coagulation analyzer (Hemochron^® Jr.) has recently been developed which performs a modified activated clotting time (ACT+) and an aPTT by using different reagents. The Hemochron^® Jr. measures the clotting time of a 5-microliter whole-blood sample by an optical detector and extrapolates the results to the activated clotting time (ACT+) or the plasma-activated partial thromboplastin time by using a validated regression analysis. We compared 124 simultaneous ACT+ and Hemochron^® ACTs, and 53 paired Hemochron^® Jr. aPTTs and hospital laboratory aPTTs, in 44 patients during coronary intervention. The Hemochron^® Jr. aPTT closely correlated with the lab aPTT (r = .79, P <.0001), and the test results were available much more rapidly than the lab aPTT (3.5 ± 1.1 vs. 56.3 ± 25.5 min, P=0.0029). A comparison of duplicate ACT+ measurements did not identify a significant difference in the means (292 ± 115 sec vs. 293 ± 112 sec, P=0.72). The ACT+ closely correlated with the Hemochron^® ACTs (r = .85, P < .0001). At baseline, the mean ACT+ (175 ± 43 sec) exceeded the Hemochron^® ACT (144 ± 36 sec) by 22% (P < .001). After heparin administration, the mean ACT+ (378 ± 74 sec) exceeded the Hemochron^® ACT (332 ± 65) by 12% (P < .001). The Hemochron^® Jr. provides a fast and reproducible methodology for measuring ACT and aPTT, using a small blood volume. Further studies are required to determine the optimal anticoagulation range when using the Hemochron^® Jr. during or after interventional procedures. (This article is a US Government work and, as such, is in the public domain in the United States of America.) © 1996 Wiley-Liss, Inc.     

Comparison between biparietal bipolar and uniparietal bipolar radio frequency ablation techniques in a simultaneous procedural setting

Purpose

To make an in vitro evaluation of the lesion size and depth produced in two different sets of radio frequency energy bipolar delivery: simultaneous biparietal bipolar (SBB) and simultaneous uniparietal bipolar (SUB).

Methods

Two separate prototypes have been built for our purpose: one to be used in SBB mode and the other to be used SUB mode. Forty left atrium samples were taken from the hearts of freshly slaughtered pigs. They were ablated into a simulator ABLABOX, where blood flow, temperature, and contact force were controlled. After being sliced into a cryotome, the samples were digitalized by a flatbed scanner, and the images were analyzed by a computer morphometric software.

Results

Transmural lesions were achieved in 18/20 samples (90%) in SBB, while SUB showed transmurality in 9/20 samples (45%). Overall maximum diameter (D_MAX) resulted larger in SUB than in SBB (2.43?±?0.30 mm, 1.62?±?0.14 mm, respectively; p?<?0.05): Moreover, maximum epicardial and endocardial diameters (D_EPI and D_ENDO, respectively) were wider in SUB group than SBB group (2.28?±?0.30 mm, 2.26?±?0.40 and 1.60?±?0.14 mm, 1.59?±?0.15 mm, respectively; p?<?0.05). We observed the same tendency in lesion depth: The total area and volume (A_TOT and V_TOT) were broader in SUB group than in SBB one (581.01?±?65.38 mm/mm², 58.10?±?6.53 mm/mm³ and 521.97?±?73.05 mm/mm², 52.19?±?7.30 mm/mm³. respectively; p?<?0.05).

Conclusions

In contrast with the smaller lesion sizes, the biparietal bipolar group showed a higher transmurality rate. These findings may suggest a better drive of the energy flow when compared with SUB lesions.

     

Temperature-controlled Radiofrequency Catheter Ablation of Accessory Pathways and Atrioventricular Nodal Reentrant Tachycardia: The 5-French Catheter Approach

Ablation with Temperature-Controlled 5-French Catheters. Introduction: In the present study, we assessed the feasibility of radiofrequency (RF) ablation of accessory pathways and AV nodal reentrant tachycardias with novel 5-French catheters with 4-mm tip electrodes using established mapping criteria and temperature-controlled power output control. Methods and Results: In this prospective study, 60 consecutive adult patients (mean age 36 ± 20 years) with accessory pathways (n = 37; 24 left-sided) or AV nodal reentrant tachycardia (n = 23) underwent RF catheter ablation. A 5-French catheter with a 4-mm tip electrode and an embedded thermistor was used for RF application. The surface of the tip electrodes was 26 mm2 compared to 38 mm² of 7-French catheters with 4-mm tip electrodes from the same catheter series. Power output was automatically and continuously adjusted according to the preset catheter tip temperature of 60° to 70°C. Pulse duration was 90 seconds. For left-sided accessory pathways, the retrograde route via the femoral artery was used. After removing the 5-French sheaths, only 4 hours of bed rest were advised. For ablation of AV nodal reentrant tachycardia, the so-called slow pathway was targeted for ablation. Acute success was achieved in 34 (92%) of 37 patients with accessory pathways and 23 (100%) of 23 patients with AV nodal reentrant tachycardia. A mean of 3 ± 4 RF pulses (median 2 pulses; range 1 to 20 pulses) was applied. The mean fluoroscopy time was 26 ± 21 minutes. No complete AV block or other procedure-related complications were observed. Recurrences occurred in 2 patients with accessory pathways and in 2 patients with AV nodal reentrant tachycardia during a follow-up of 9 ± 4 months. Conclusions: Temperature-controlled RF ablation of accessory pathways and AV nodal reentrant tachycardia in adults using 5-French catheters is feasible, effective, and safe. Ablation with 5-French catheters might help to reduce the complication rate of catheter ablation techniques.