Semi-compliant Balloon Research Articles

Balloon-Assisted Coiling of the Cavernous Sinus to Treat Direct Carotid Cavernous Fistula

This study evaluated clinical and neuroradiological results in 13 consecutive patients with spontaneous and traumatic direct carotid cavernous fistulas treated at our center between January 2006 and September 2012. All patients were treated by coiling of the cavernous sinus. Coiling was always performed while a semi-compliant non-detachable balloon was temporarily inflated in the internal carotid artery. This technique (balloon-assisted coiling) permitted a clear visualization of the fistula, facilitated coil positioning and protected the patency of the artery. All patients' clinical data and radiological examinations were reviewed; nine patients underwent radiological and clinical follow-up, with a mean duration of 3.8 years (range: six months-six years). Overall results at discharge showed a complete occlusion of the fistula in seven patients (7/13, 54%) and a resolution of symptoms in eight patients (8/12, 67%). Radiological follow-up showed complete occlusion of the fistula in all patients (9/9, 100%) and clinical follow-up showed a resolution of symptoms in eight patients (8/9, 89%) and persistent symptoms in one (1/9, 11%). No procedure-related complications occurred. Balloon-assisted coiling of the cavernous sinus for the treatment of direct carotid cavernous fistulas proved an effective and safe technique, both in angiographic and clinical terms, and may be considered a technical improvement.

Impact of longitudinal stent elongation during percutaneous coronary intervention

Background: Longitudinal stent deformation is one of the hottest topics. We experienced a case of stent elongation during stent deployment. Considering this, the following tests were performed. Methods: Four kinds of drug eluting stents (DES: Xience Prime (XP), Plomus Element (PE), Nobori (N) and Cypher select plus (CY)) with three 3x28mm stents of each were used for each test. In test 1, all stents were dilated five times at rated burst pressure (RBP) in air pressure. In test 2 and 3, all stents (except CY in test 3) were implanted in a tapered phantom model with the proximal and distal diameter being 3.5mm and 3mm respectively, at nominal pressure and single post-dilation to proximal portion of the stents was performed with RBP using 3.5x15mm semi-compliant balloon (SC) (Test 2) and 3.5x15mm high-pressure balloon (HP) (Test 3). Stent length before and after each tests were measured. To disclose the relationship between stent elongation and the types of balloon catheters (BC) used, four SC (A to D) and three HP (E to G) were also tested. Three 3mm BC with two types of the length were tested (short: 15mm in SC and 8-10mm in HP, long: 20mm in SC and 15mm in HP). All BC were inflated at nominal pressure and RBP in air pressure and the change of length (%) were checked. Results: Lengths of stent elongation was significantly different between all DESs in Test 1. However, no significant difference was observed in test 2 and 3 except for CY (Table 1). All BC elongated with RBP inflation in significantly different rates, however, similar results between short BC and long BC were observed (Table 2). View this table: Table 1. Elongation of DESs View this table: Table 2. Elongation of BC Conclusion: Longitudinal stent elongation was observed in all kinds of DESs tested, especially in new generation stents. We must considerer this phenomenon when deploying stents, especially long ones.

Finite element analysis of balloon‐expandable coronary stent deployment: Influence of angioplasty balloon configuration

Today, the majority of coronary stents are balloon-expandable and are deployed using a balloon-tipped catheter. To improve deliverability, the membrane of the angioplasty balloon is typically folded about the catheter in a pleated configuration. As such, the deployment of the angioplasty balloon is governed by the material properties of the balloon membrane, its folded configuration and its attachment to the catheter. Despite this observation, however, an optimum strategy for modelling the configuration of the angioplasty balloon in finite element studies of coronary stent deployment has not been identified, and idealised models of the angioplasty balloon are commonly employed in the literature. These idealised models often neglect complex geometrical features, such as the folded configuration of the balloon membrane and its attachment to the catheter, which may have a significant influence on the deployment of a stent. In this study, three increasingly sophisticated models of a typical semi-compliant angioplasty balloon were employed to determine the influence of angioplasty balloon configuration on the deployment of a stent. The results of this study indicate that angioplasty balloon configuration has a significant influence on both the transient behaviour of the stent and its impact on the mechanical environment of the coronary artery.

Coronary Extramural Haematoma Caused by Perforation during Left Main Coronary Artery Intervention

A year-old male patient with a background of quintuple coronary artery by-pass graft surgery 16 years ago presented to our department with symptoms consistent with unstable angina pectoris. Previous angiography performed in 2001 revealed occluded saphenous vein grafts to the left anterior descending (LAD), right coronary, obtuse The presence of pericardial effusion was immediately ruled out by echocardiography and because of absence of myocardial contrast staining heparin was not reversed. Subsequent intravascular ultrasound (IVUS) examination revealed a minimal lumen area of ≥11.00 mm2 throughout the stented segment despite stent underexpansion at marginal and first diagonal (DA) arteries, and patent left internal mammary artery (LIMA) graft to a second DA. At the same session he underwent percutaneous coronary intervention with bare metal stent implantation for significant mid to distal LAD artery disease. Since then, the patient was stable with Canadian angina class I. During this admission, his echocardiogram revealed an ejection fraction of 40%, akinesia of the inferior wall which was known to be predominantly infarcted and hypokinesia of the basal and mid anterior septum. Coronary angiography (Fig. 1) showed subocclusive calcified and angulated distal left main coronary artery (LMCA) disease, significant ostial LAD artery disease, collateralised occlusion of the distal LAD, left circumflex (LCx) and right coronary arteries, tight proximal disease of a first DA and patent LIMA graft to a second DA. Given these findings we proceeded with stent angioplasty to the LMCA-ostial LAD artery lesion. After a series of predilations with semicompliant balloons, a 4.0 mm × 24 mm drug-eluting stent was the LMCA opposite to the LCx artery ostium and at the LAD artery ostium. Cross-sections of IVUS at the site of perforation revealed an echo-dim pattern suggesting an extramural haematoma and local stent underexpansion with a compression effect by the haematoma whereas the site of blood entry into the adventitia was identified at the distal margin of the haematoma adjacent to a fibrocalcific plaque (Fig. 2). Given the adequate minimal lumen area further stent postdilation was not performed to avoid the risk of frank coronary perforation. The patient was maintained on dual antiplatelet therapy and discharged home after a two-day uneventful hospital course. He remained stable eight months post stenting with Canadian angina class I and no evidence of a cardiovascular event. Extramural haematoma that is accumulation of blood outside the arterial wall in the adventitia tissue is a rare complication of percutaneous coronary intervention and is thought to develop secondary to adventitial dissection implanted from the ostium of the LMCA across the stenosis into the LAD artery at 8 atms. Control angiography after [1–3]. It presents with an echo-dim pattern due to the dilution of the red blood cells and dissemination throughout

Intravascular optical coherence tomography to characterize tissue deformation during angioplasty: preliminary experiments with artery phantoms

We explored the potential of intravascular optical coherence tomography (IVOCT) to assess deformation during angioplasty balloon inflation. Using a semi-compliant balloon and artery phantoms, we considered two experimental scenarios. The goal for the first scenario was to investigate if variation in the elasticity of the structure surrounding the balloon could be sensed by IVOCT monitoring. In this scenario, we used three single-layer phantoms with various mechanical properties. Image analysis was performed to extract the inner and outer diameters of the phantoms at various pressures. The goal for the second scenario was twofold. First, we investigated the IVOCT capability to monitor a more complex balloon inflation process. The balloon was in a folded state prior to inflation. This allowed studying two stages of deformation: during balloon unfolding and during balloon expansion. Second, we investigated IVOCT capability to monitor the deformation in a three-layer phantom used to better mimic a true artery. So, not only were the IVOCT images processed to provide the inner and outer diameters of the phantom, but the layer thicknesses were also determined. In both scenarios, IVOCT monitoring revealed to be very efficient in providing relevant information about the phantom deformation during balloon inflation.

Effect of intravascular ultrasound-guided adjuvant high-pressure non-compliant balloon post-dilation after drug-eluting stent implantation

Drug-eluting stent (DES) expansion characteristics after aggressive high-pressure post-dilation using a non-compliant (NC) balloon have not been fully investigated. We evaluated 58 patients with native coronary lesions treated with DESs [24 paclitaxel eluting stents (PES) and 34 sirolimus-eluting stents (SES)]. After post-dilation (12-14atm) using a stent-mounted semi-compliant balloon to reduce stent edge injury, adjuvant high-pressure post-dilation using NC balloon was performed within the stents. Stent size, stent length, and NC balloon size were selected based on preinterventional intravascular ultrasound (IVUS) assessment. Stent underexpansion was defined according to criteria of the Multicenter Ultrasound Stenting in Coronaries (MUSIC) study as a minimal stent cross-sectional area <90% of the average reference lumen area. Resultant endpoint was to obtain optimal stent expansion. Serial changes of stent expansion and stent symmetry were calculated in each group. After stent-mounted semi-compliant balloon post-dilation, both stents could not achieve adequate percent stent expansion (PES 73±18% vs. SES 67±9%, p=0.38). After high-pressure post-dilation using an NC balloon, percent stent expansion was 97±14% in PES and 91±13% in SES, respectively (p=0.25). Axial stent symmetry indices also significantly improved in both groups. Although radial stent symmetry indices improved significantly in PES group, those in the SES group had no significant changes. Finally, frequency of stent underexpansion significantly reduced, 87-20% in PES and 92-15% in SES, respectively (p=0.01) without any significant stent edge injury. DES expansion improved safely after adjuvant high-pressure post-dilation using an NC balloon under IVUS guidance.

Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester

We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, consequently, a technique to improve the balloon manufacturing process. A custom-built swept-source optical coherence tomography system is used for real-time imaging. A semicompliant balloon with a nominal diameter of 4 mm is fabricated for the experiments. Imaging results correspond to balloon deployment in air and inside an artery phantom. A characterization of the balloon diameter, wall thickness, compliance, and elastic modulus is provided, based on image segmentation. Using the images obtained from the probe pullback, a three-dimensional visualization of the inflated balloon is presented.

Impact of Different Re-stenting Strategies on Expansion of a Drug-Eluting Stent Implanted to Treat Bare-Metal Stent Restenosis

We used intravascular ultrasound (IVUS) to compare the expansion of drug-eluting stents (DES) implanted to treat bare-metal stent (BMS) restenosis after 3 common re-stenting strategies. A total of 80 consecutive BMS restenotic targets were re-stented either directly (n = 30, group 1) or after low-pressure (<8 atm) pre-dilation with an undersize regular balloon (n = 16, group 2) or after high-pressure (>12 atm) pre-dilation with a semicompliant balloon the same or greater diameter as the original BMS diameter (n = 34, group 3). More patients from groups 2 and 3 had diabetes mellitus. The targets in group 1 were more proximal and focal. Lesions from groups 2 and 3 were more severe. The size and deployment pressure of the DESs and the achieved angiographic results were all similar. The post-intervention minimum stent area and the percentage of expansion of DES (minimum stent area/distal reference lumen area x 100%) were, however, both significantly larger in group 3 (6.4 +/- 1.5 mm(2) in group 3 vs 5.6 +/- 1.6 mm(2) in group 1 vs 4.4 +/- 1.4 mm(2) in group 2, p <0.001; and 88 +/- 30% in group 3 vs 74 +/- 14% in group 1 vs 73 +/- 23% in group 2, p = 0.021). A post-intervention minimum stent area <5.0 mm(2) was seen in only 3 lesions in group 3 (8.8%) versus 14 in group 1 (46.7%) and 11 in group 2 (68.8%; adjusted odds ratio 0.11, 95% confidence interval 0.03 to 0.38, p <0.001). Overall, the acute lumen gain was mainly from BMS re-expansion; however, the BMS volume increased the most in group 3 (p <0.001). In conclusion, high-pressure pre-dilation leads to superior post-intervention expansion of DESs implanted to treat BMS restenosis, regardless of the original expansion because of the greater BMS re-expansion.

Use of the Angiosculpt Scoring Balloon for Infrapopliteal Lesions in Patients with Critical Limb Ischemia: 1-Year Outcome

The AngioSculpt Scoring Balloon Catheter (AngioScore, Inc., Fremont, CA) is composed of a semicompliant balloon encircled by three nitinol spiral struts providing targeted lesion scoring on balloon inflation. Between April 2005 and April 2006, procedural and follow-up data on 31 patients (mean age 76 years; 54.8% males) endovascularly treated for severe infrapopliteal disease were collected. The AngioSculpt catheter was used to treat 36 complex, tibioperoneal, atherosclerotic lesions. All patients had symptomatic critical limb ischemia (Rutherford 4-5) and single-vessel runoff to the ankle. Complication-free survival at 1 month was the safety end point, whereas primary patency and limb salvage were the efficacy end points evaluated at 1 year. The AngioSculpt balloon was successfully inflated in all 36 target lesions. Eleven patients (35.5%) required additional stenting for minor dissections or suboptimal stenosis reduction. The 1-month complication-free survival was 96.8%. One-year survival, primary patency, and limb salvage rates were 83.9 +/- 6.6%, 61.0 +/- 9.3%, and 86.3 +/- 6.4%, respectively. The 1-year data show the AngioSculpt Scoring Balloon Catheter to be an effective and safe treatment for infrapopliteal, atherosclerotic lesions in patients with critical limb ischemia. However, more patients, a longer follow-up, and randomized studies comparing it with conventional balloon angioplasty and stenting in the infrapopliteal region are required.

Intravascular Ultrasound Evaluation of Optimal Drug-Eluting Stent Expansion After Poststent Balloon Dilation Using a Noncompliant Balloon Versus a Semicompliant Balloon (from the Poststent Optimal Stent Expansion Trial [POET

The impact of type of balloon such as noncompliant (NC; Quantum) or semicompliant (SC; Maverick(2)) used after stent dilation on optimal stent expansion (OSE) has not been established for drug-eluting stents (DESs). We conducted a prospective multicenter, randomized study to compare NC with SC balloons after stent balloon dilatation. A total of 301 patients (127 men, 83 women, 62 +/- 9 years of age) treated with a DES (sirolimus-eluting stent [SES], n = 152; paclitaxel-eluting stent, n = 149) were included. OSE followed the definition of the Multicenter Ultrasound Stenting in Coronaries (MUSIC) study. The primary end point was the incidence of OSE using intravascular ultrasound according to type of balloon. Baseline characteristics of each group showed no significant differences. OSE in the SC balloon group was achieved at higher rates than the NC balloon group (53 +/- 35%, vs 73 +/- 48%, p = 0.022 in all stents; 25 +/- 33%, vs 36, 48%, p = 0.051 in SESs). However, any differences in the achievement of OSE between the NC and SC balloon groups were not present in paclitaxel-eluting stents. In conclusion, despite postadjuvant balloon inflations with high pressures, underexpansion of the DES was seen commonly. Between the 2 types of balloon for adjuvant dilation after DES implantation, same-size SC balloons could be more useful for obtaining OSE than NC balloons, especially in SESs.

Nonrandomized Comparison of Coronary Stenting Under Intravascular Ultrasound Guidance of Direct Stenting Without Predilation Versus Conventional Predilation With a Semi-Compliant Balloon Versus Predilation With a New Scoring Balloon

This study was conducted to determine the influence of lesion preparation using the AngioSculpt balloon on final stent expansion. Stent expansion remains an important predictor of restenosis and subacute thrombosis, even in the drug-eluting stent (DES) era. In these patients, the role of different predilation strategies has yet to be established. Two hundred ninety-nine consecutive de novo lesions treated with 1 >2.5-mm DES (Cypher or Taxus) under intravascular ultrasound guidance without postdilation, using 3 implantation strategies, were studied: (1) direct stenting without predilation (n = 145), (2) predilation with a conventional semi-compliant balloon (n = 117), and (3) predilation with the AngioSculpt balloon (n = 37). Stent expansion was defined as the ratio of intravascular ultrasound-measured minimum stent diameter and minimum stent area to the manufacturer's predicted stent diameter and area. These ratios were larger after AngioSculpt predilation, and a greater percentage of stents had final minimum stent areas >5.0 mm(2) (another commonly accepted criterion of adequate DES expansion). Lesion morphology, stent and lesion length, and reference vessel size did not affect DES expansion. In conclusion, in this observational, nonrandomized study, pretreatment with the AngioSculpt balloon enhanced stent expansion and minimized the difference between predicted and achieved stent dimensions.

An integrated semicompliant balloon ultrasound catheter for quantitative feedback and image guidance during stent deployment

An integrated balloon ultrasound catheter prototype was designed to image from inside the balloon for real-time guidance during stent deployment. It was fabricated using a semicompliant balloon material (polyethylene) and a 20 MHz, 64-element circumferential ultrasound array. A commercial stent, nominally 4.4 mm in diameter and 12 mm in length, was used for a phantom study and placed along the length of the integrated balloon ultrasound catheter. A rubber phantom was created with an elastic modulus of 175 kPa with a 4.36 mm diameter lumen. Real-time balloon pressure measurements were recorded using a digital pressure sensor, and real-time radio-frequency (RF) data were captured as the balloon was inflated. The slope of the area-pressure ratio (APR) was compared to a reference measure of the balloon and stent expanded in water to determine a measure for optimal stent deployment. The results clearly indicate stent deployment at 11.1 atm using this metric. The APR slope could serve as quantitative feedback parameter for guiding stent deployment to reduce arterial injury and subsequent restenosis. After the stent deployment experiment, RF data were captured as the balloon catheter was moved along the length of the stent in pullback mode to confirm successful stent deployment. Ultimately, an integrated balloon ultrasound catheter could serve as a single catheter intervention device by providing real-time intravascular ultrasound (IVUS) imaging and quantitative feedback during stent deployment.

Rupture of the Renal Artery After Cutting Balloon Angioplasty in a Young Woman With Fibromuscular Dysplasia

A 24-year-old woman with uncontrollable high blood pressure for 3 months had significant stenosis of the left renal artery caused by fibromuscular dysplasia (FMD). The lesion was resistant to percutaneous transluminal angioplasty at 18 atm with a semicompliant balloon. Angioplasy with a 6 x 10 mm cutting balloon (CB) caused rupture of the artery. Low-pressure balloon inflation decreased but did not stop the leak. An attempt to place a stent-graft (Jostent; Jomed, Rangendingen, Germany) failed, and a bare, 6-mm balloon-expandable stent (Express SD; Boston Scientific, MN) was deployed to seal the leak, which had decreased considerably after long-duration balloon inflation. The bleeding continued, and the patient underwent emergent surgical revascularization of the renal artery with successful placement of a 6-mm polytetrafluoroethylene bypass graft. CBs should be used very carefully in the treatment of renal artery stenosis, particularly in patients with FMD.

First clinical experience with the premounted balloon‐expandable serpentine stent: Acute angiographic and intermediate‐term clinical results

The beStent-Artist coronary stent is a newly developed, stainless steel coronary stent with a serpentine tubular design and terminal stent markers, premounted on a semicompliant balloon. During this pilot evaluation we aimed to test the acute clinical and angiographic results, short-term (30 days) and 6-month clinical results. A total of 57 stents were used to treat 43 lesions in 40 patients. Deployment strategy included predilatation, stent deployment, balloon repositioning to match the distal end of the balloon to the distal stent marker, and subsequent 12–14 atm postdilatation. There were two cases of stent dislodgment, but no procedural complications. In four cases, stent recrossing with another balloon was necessary. In two of these cases, distal dissections were observed and treated with another stent. The minimal lumen diameter (MLD) increased from 0.84 ± 0.52 mm at baseline to 2.7 ± 0.62 mm at the end of the procedure (a corresponding decrease in diameter stenosis from 78.6 > 16.4 to 18.2 ± 10.7%). The acute gain was 1.89 ± 0.61mm. No adverse events occurred by 30 days. During six months, 7/40 (18.5%) of patients required target vessel revascularization due to in-stent restenosis. In summary, the premounted beStent-Artist can be delivered and deployed with favorable immediate results and high success rate with favorable long-term recurrent event rates.Cathet. Cardiovasc. Intervent. 46:249–253, 1999. © 1999 Wiley-Liss, Inc.

Angiographic follow‐up and clinical experience with the flexible tantalum cordis stent

The Cordis stent is a flexible, highly radioopaque intracoronary stent engineered from a single Tantalum filament folded into a sinusoidal helical coil. It is premounted on a semicompliant balloon expandable stent delivery system. From September 1995–March 1996, 147 Cordis stents were deployed in 105 patients (aged 58 ± 12 yr, 71% male). Clinical indications for stenting were unstable angina in 59 (55%), stable angina in 41 (38%), and acute myocardial infarction in 7 (7%). The target vessel was the right coronary artery in 45%, the left anterior descending in 31%, and the circumflex artery in 22%. One stent was deployed in a vein graft, and one stent was deployed in a left internal mammary artery graft. Stent deployment was achieved in all but one patient. Acute in-stent thrombosis occurred in 3 patients (2.9%). Two of these patients required urgent coronary artery bypass surgery. Subacute stent thrombosis occurred in 2 patients (1.9%). Minimum lumen diameter increased from 0.70 ± 0.41 mm to 3.50 ± 0.60 mm following stent placement. All patients received aspirin. Eighty-one patients (77%) received ticlopidine, and 4 patients (4%) received warfarin therapy. The mean hospital stay was 3.4 ± 2.3 days. Six-month follow-up angiography was performed on 50 out of 55 eligible patients at one of the two institutions involved in this study. Computer-assisted quantitative coronary angiography defined a restenosis rate of 26%. Repeat revascularization was required in 8 patients (14.5%) at 6-mo follow-up. The Tantalum Cordis intracoronary stent is an effective and safe means of treating coronary lesions, even in patients with unstable ischemic syndromes. Acute and subacute rates of in-stent thrombosis were acceptable, and the long-term angiographic restenosis rates and need for repeat revascularization were favorable. Cathet. Cardiovasc. Diagn. 43:168–173, 1998. © 1998 Wiley-Liss, Inc.

Angiographic follow-up and clinical experience with the flexible Tantalum Cordis stent.

The Cordis stent is a flexible, highly radioopaque intracoronary stent engineered from a single Tantalum filament folded into a sinusoidal helical coil. It is premounted on a semicompliant balloon expandable stent delivery system. From September 1995-March 1996, 147 Cordis stents were deployed in 105 patients (aged 58+/-12 yr, 71% male). Clinical indications for stenting were unstable angina in 59 (55%), stable angina in 41 (38%), and acute myocardial infarction in 7 (7%). The target vessel was the right coronary artery in 45%, the left anterior descending in 31%, and the circumflex artery in 22%. One stent was deployed in a vein graft, and one stent was deployed in a left internal mammary artery graft. Stent deployment was achieved in all but one patient. Acute in-stent thrombosis occurred in 3 patients (2.9%). Two of these patients required urgent coronary artery bypass surgery. Subacute stent thrombosis occurred in 2 patients (1.9%). Minimum lumen diameter increased from 0.70+/-0.41 mm to 3.50+/-0.60 mm following stent placement. All patients received aspirin. Eighty-one patients (77%) received ticlopidine, and 4 patients (4%) received warfarin therapy. The mean hospital stay was 3.4+/-2.3 days. Six-month follow-up angiography was performed on 50 out of 55 eligible patients at one of the two institutions involved in this study. Computer-assisted quantitative coronary angiography defined a restenosis rate of 26%. Repeat revascularization was required in 8 patients (14.5%) at 6-mo follow-up. The Tantalum Cordis intracoronary stent is an effective and safe means of treating coronary lesions, even in patients with unstable ischemic syndromes. Acute and subacute rates of in-stent thrombosis were acceptable, and the long-term angiographic restenosis rates and need for repeat revascularization were favorable.

Coronary artery stenting without anticoagulation, aspirin, ultrasound guidance, or high balloon pressure: prospective study of 1,051 consecutive patients.

Between March 1994 and November 1995, 1,212 coronary stents were implanted in 1,051 consecutive patients at our institution with the following protocol: daily pre- and poststenting treatment with ticlopidine 500 mg without aspirin, implantation under angiographic guidance, without ultrasound, with semi-compliant balloons inflated at 10 bars. Stenting was indicated after failure of balloon angioplasty (bail-out, dissection, elastic recoil) in 27% of the patients and considered as elective (de novo, restenosis, chronic occlusion, saphenous vein grafts) in 73% of the cases. During the 30-day follow-up period, stent thrombosis occurred in 11 patients (1.0%) and vascular access-site complications in three patients (0.3%). Thirteen patients (1.1%) died, 10 from previous left ventricular failure, 3 (0.3%) from subacute thrombosis. Multivariate analysis revealed that the size of the last balloon used was associated with subacute stent thrombosis Thus, in nonselected patients, placement of coronary stents may be safely achieved without use of warfarin, post procedural heparin, high balloon pressure, or ultrasound guidance. Antiplatelet therapy with ticlopidine and angiographic guidance result in a stent thrombosis rate of 1% and a vascular complication rate of 0.3%.

Angioplasty balloon compliance: Can in vivo size be predicted from in vitro pressure profile measurements?

This study was undertaken to determine whether the behavior of angioplasty balloons within coronary arteries may differ from that anticipated from data provided by the manufacturers. In particular, the in vitro pressure-diameter profiles may not truly represent in vivo sizes. Thus, we assessed the degree of correlation of in vitro with in vivo measurements obtained during routine angioplasty practice. In vivo size of 2.5 mm compliant (n = 8) and 3 mm semicompliant (n = 8) balloons was assessed using quantitative angiography for first, second, and third inflations. In vivo size was less than expected from in vitro measurements. In general balloon diameter increased with inflation pressures up to 8 atmospheres, and some degree of elastic recoil was evident with both balloon types after the last inflation. In vivo balloon size may not be accurately predicted from manufacturers' published data. Size is more likely to be affected by factors such as lesion characteristics and elasticity of the vessel wall than by balloon material compliance characteristics.