Prolonged Inflation Research Articles

New concept in coronary angioplasty: Dilatation with a helical balloon that allows simultaneous autoperfusion

These preclinical studies investigate a new concept in coronary angioplasty and balloon catheter technology (the P100 catheter). The study sought to evaluate the morphology of experimental coronary arterial plaques dilated with the P100 in comparison to standard balloons, to determine the in vitro flow rates occurring during the inflation of the P100 in comparison to available perfusion catheters, and to assess the in vivo coronary flow velocity and the presence of ischemia during prolonged inflations with the P100. The development of myocardial ischemia is a major limitation of standard balloon angioplasty. To limit ischemia, autoperfusion catheters have been developed, in which blood flows through the balloon in the central catheter shaft. However, as the flow lumen profile is reduced to enhance the performance of these devices, so is the accompanying flow. An angioplasty catheter was designed to evaluate the feasibility of continuous autoperfusion around the dilatation balloon. The balloon surface was engineered to develop a helical trough for blood flow to occur during inflation. Arterial plaque morphology following angioplasty with the P100 (n = 8) and with standard balloons (n = 8) was evaluated in a swine model. In vitro flow rates during inflation of the P100 and available perfusion catheters were determined using 33% glycerol solution. In vivo coronary flow velocity was determined with a Doppler-tipped wire during 60-min continuous inflations with the P100, and 15-sec inflations with a standard balloon in 12 vessel segments in 7 dogs; using 3.0–3.5-mm-diameter balloons. All lesions were successfully dilated (<50% luminal diameter stenosis) with the P100 and standard balloons. There were no morphologic differences in plaques dilated with P100 compared to standard balloons. In vitro flow rates with conventional 3.0-mm balloon perfusion catheters ranged from 27.1 ± 2.1 ml/min (RX Flowtrack™) to 38.7 ± 0.9 ml/min (Stack Perfusion™), P < .05. Flow with the P100 ranged from 54.8 ± 4.3 ml/min (2.5-mm balloon) to 103.2 ± 4.5 ml/min (3.5-mm balloon), P <.05. Distal average peak coronary flow velocity during prolonged P100 inflations varied from 69 ± 7% of baseline at 5 min to 83 ± 8% of baseline at 40 min, with an upward trend in velocity the longer the balloon was inflated. Hemodynamics remained stable. Experimental plaques are successfully dilated with a helical balloon by a mechanism that appears similar to the dilatation mechanism of standard balloons. These preclinical studies show that angioplasty and autoperfusion can be accomplished by a balloon that does not have complete surface area contact with the vessel wall. A gap created by the helix can thus provide a conduit for blood flow. Clinical studies will determine whether this innovation, which alters the tubular geometry of current angioplasty balloons, will provide autoperfusion and equivalent dilatation effects in humans. Cathet Cardiovasc Diagn 40:109–116, 1997. © 1997 Wiley-Liss, Inc.

New concept in coronary angioplasty: dilatation with a helical balloon that allows simultaneous autoperfusion.

These preclinical studies investigate a new concept in coronary angioplasty and balloon catheter technology (the P100 catheter). The study sought to evaluate the morphology of experimental coronary arterial plaques dilated with the P100 in comparison to standard balloons, to determine the in vitro flow rates occurring during the inflation of the P100 in comparison to available perfusion catheters, and to assess the in vivo coronary flow velocity and the presence of ischemia during prolonged inflations with the P100. The development of myocardial ischemia is a major limitation of standard balloon angioplasty. To limit ischemia, autoperfusion catheters have been developed, in which blood flows through the balloon in the central catheter shaft. However, as the flow lumen profile is reduced to enhance the performance of these devices, so is the accompanying flow. An angioplasty catheter was designed to evaluate the feasibility of continuous autoperfusion around the dilatation balloon. The balloon surface was engineered to develop a helical trough for blood flow to occur during inflation. Arterial plaque morphology following angioplasty with the P100 (n = 8) and with standard balloons (n = 8) was evaluated in a swine model. In vitro flow rates during inflation of the P100 and available perfusion catheters were determined using 33% glycerol solution. In vivo coronary flow velocity was determined with a Doppler-tipped wire during 60-min continuous inflations with the P100, and 15-sec inflations with a standard balloon in 12 vessel segments in 7 dogs; using 3.0-3.5-mm-diameter balloons. All lesions were successfully dilated (< 50% luminal diameter stenosis) with the P100 and standard balloons. There were no morphologic differences in plaques dilated with P100 compared to standard balloons. In vitro flow rates with conventional 3.0-mm balloon perfusion catheters ranged from 27.1 +/- 2.1 ml/min (RX Flowtrack) to 38.7 +/- 0.9 ml/min (Stack Perfusion), P < .05. Flow with the P100 ranged from 54.8 +/- 4.3 ml/min (2.5-mm balloon) to 103.2 +/- 4.5 ml/min (3.5-mm balloon), P < .05. Distal average peak coronary flow velocity during prolonged P100 inflations varied from 69 +/- 7% of baseline at 5 min to 83 +/- 8% of baseline at 40 min, with an upward trend in velocity the longer the balloon was inflated. Hemodynamics remained stable. Experimental plaques are successfully dilated with a helical balloon by a mechanism that appears similar to the dilatation mechanism of standard balloons. These preclinical studies show that angioplasty and autoperfusion can be accomplished by a balloon that does not have complete surface area contact with the vessel wall. A gap created by the helix can thus provide a conduit for blood flow. Clinical studies will determine whether this innovation, which alters the tubular geometry of current angioplasty balloons, will provide autoperfusion and equivalent dilatation effects in human.

Rotura coronaria encapsulada tras implantación de stent

We report a case of coronary encapsulated rupture following stent implantation in the distal anastomosis of a saphenous by-pass graft to the left anterior descending coronary artery that evolved well with conservative treatment. The patient did not require pericardiocentesis and was treated with prolonged inflations with low pressure autoperfusion balloon at the rupture point. Pericardial adherences related to a previous coronary surgery probably limited the bleeding process avoiding hemodynamic collapse.

Effects of prolonged sequential balloon inflations on results of coronary angioplasty

In percutaneous transluminal coronary angioplasty (PTCA), prolonged balloon inflations using perfusion balloon catheters have shown a higher procedural success rate and fewer in-hospital complications than short balloon inflations. However, perfusion balloons have well-recognized limits for routine use. This study assessed the effects of a prolonged cumulative occlusion time obtained with sequential balloon inflations using a routine balloon catheter, applicable to all lesions, and compared these results with those obtained with standard short balloon inflations. Three hundred ten lesions (in 289 patients) were randomized to either standard (3 to 5 inflations ≤1 minute each; n = 161) or prolonged (3 to 5 inflations of 3 to 5 minutes each; n = 149) balloon inflations. Angiographic success (residual stenosis < 50% and no dissection ≥D1) was assessed at the end of this “protocol” phase. Further dilatation was performed if required (“adjuncfive” phase). Systematic repeat catheterization was scheduled 4 to 6 months later. Cumulative inflation time was 198 ± 58 seconds in the “standard” group versus 782 ± 303 seconds in the “prolonged” group. At the end of the protocol phase, the success rate was higher after prolonged than after standard dilatation (92% vs 80%; p < 0.002), with less frequent dissections (14% vs 30%; p = 0.0009). At the end of the adjunctive phase, required for 12 patients in the prolonged group and 32 patients in the standard group (p = 0.003), results were comparable in the 2 groups and the restenosis rate was similar at 6 months. The prolonged cumulative occlusion time achieved with sequential balloon inflations using a routine balloon catheter improves the immediate results of PTCA. Repeat catheterization shows no effect of prolonged sequential inflations on the restenosis rate.

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty.

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty (PTCA)-with an autoperfusion balloon or active system-facilitates prolonged balloon inflation. Prolonged inflations may tack up intimal dissections and improve the primary angioplasty result in complex lesions. Additionally, distal perfusion may reduce the likelihood of cardiogenic shock during high-risk PTCA. Autoperfusion balloons are most frequently used to treat acute or threatened closure. There currently is no prospective clinical study showing that stent implantation for this complication is more successful and more cost-effective. The blood flow rates through autoperfusion balloons may not abolish myocardial ischemia, and higher flow rates can often be achieved with pumps. Therefore, during high-risk PTCA, pumps may be preferred to prevent hemodynamic collapse. Clinical application of perfusion pumps is hampered by the risk for mechanical hemolysis during prolonged perfusion and the high velocity of the bloodstream that exits the PTCA catheter, causing distal vessel wall trauma.

Ultrex Cylinders: Problems with Uncontrolled Lengthening (The S-Shaped Deformity)

Purpose We investigated whether the AMS Ultrex [dagger] cylinder, developed to provide cylinder lengthening while controlling girth expansion, acted as a tissue expander and, thus, promoted penile lengthening. [dagger] American Medical Systems, Minnetonka, Minnesota. Materials and Methods Between December 1990 and January 1992, 59 AMS Ultrex prostheses were implanted. Cylinder length corresponded to intracorporeal measurements. The results of lengthening and occurrence of an S-shaped deformity were statistically analyzed. Results No penile lengthening occurred. In 19 patients (32 percent) cylinder replacement was required for the S-shaped deformity. Conclusions Ultrex cylinders should be downsized and prolonged inflation should be avoided. They should not be implanted in cases of Peyronie's disease, or to replace malleable or self-contained inflatable implants.

Changes in patient treatment after abrupt closure complicating percutaneous transluminal coronary angioplasty: A historic perspective

This study compares the incidence and management of acute closure complicating coronary angioplasty in three historic populations of patients having undergone the procedure at the same center: group 1 (n = 146of881) (“early years” of angioplasty, 1980 to 1986), group 2 (n = 133of1781) (bailout stenting learning curve, 1990 to 1992), and group 3 (n = 34of525) (1993). The incidence of acute closure decreased from group 1 (146 [17%] of 881) to groups 2 and 3 (147 [6%] of 2306); (p < 0.001). Management of the occlusion changed over the years, with less emergency coronary bypass surgery ([36%] 52 of 146, 15 [13%] 113, and 3 [9%] of 34), respectively, p < 0.01) and more repeat angioplasty (70 [48%] of 146; 87 [78%], of 113, and 30 [88%] of 34, p < 0.001). The use of prolonged inflations (>10 minutes) and stenting increased from group 2 (15 [13%] of 113 and 16 [14%] of 113, respectively) to group 3 (12 [35%] of 34, and 10 [30%] of 34, respectively). In-hospital death occurred in 18 (12%) of 146, 7 (6%) of 113), and (2 (6%) of 34) patients in the three groups. Acute myocardial infarction decreased from 64% to 46% and 27%, respectively (p < 0.01). Overall, the number of patients free of events at hospital discharge increased from 38 (26%) of 146 to 53 (47%) of 113 (p < 0.001) and to 23 (68%) of 34 (p < 0.001). In group 3, 80% of the patients treated with prolonged balloon inflations or stenting were free of events compared with 50% of the others (p = 0.07). Improvement in the management of acute occlusion complicating coronary angioplasty results from increased experience in this difficult setting and also from the use of new angioplasty techniques such as bailout stenting or prolonged balloon inflations.

Kainic acid lesions of the parvocellular paraventricular nucleus of the hypothalamus abolish neuropeptide y stimulated gastric activity

We have previously shown centrally administered Neuropeptide Y (NPY) to stimulate gastric acid secretion and motility via a vagal pathway. Further, using Fog immunohistochemistry in combination with both intraeerebroventricular (ICV) and micro-injections of NPY in and around the paraventrieular nucleus (PVH), we have proposed the parvocellular (pPVH) region of the PVH to mediate this excitation of gastric function. The purpose of this study was to examine this proposed mechanism with selective lesioning of the pPVH with kainic acid. Male Sprague-Dawley rats were randomly placed into one of four treatment groups: i) untreated, saline injection; 2) untreated, NPY injection; 3) sham-treated, NPY injection; and 4) kainate-treated, NPY injection. Groups 3 and 4 were pre-treated, at least 3 days prior to experimentation, as follows: bilateral injections of either PBS vehicle (100 hi) or kainic acid (0.5-1.0/zg/50-100 nl) were performed with a glass micro-injector inserted into the pPVH. On the day of experimentation, all rats were anaesthetized with urethane, implanted with ICV guide cannulae and set up to continuously monitor gastric acid secretion 0zeq. H ÷) and motility (mmHg). Following stabilization, rats were injected (ICV) with either saline (5 #l) or NPY (200 pM/5 FI). At the end of the experiment, rats were perfnsed with 4% paraformaldehyde and the brains were removed, fixed and sectioned (40 t~m). Sites of kainate lesions were later verified using KluverBarrera staining. Increased acid secretion and motility were observed within 10 + 2 rain following ICV injections of NPY in both untreated and sham-treated groups, which did not significantly differ from one another. Both gastric parameters followed similar time courses by peaking within 30 rain of injection and returning to pre-injection baseline levels within 60-75 rain of injection. Both the untreated saline-injected and the pPVH kainate-treated NPY-injected groups showed no significant enhancement, of either gastric acid secretion or motility. Further, kainate injections located outside of the pPVH did not prevent NPY-induced gastric activity. We conclude that NPY mediates an excitation of gastric acid secretion and motility by acting on neurons of the pPVH. Supported by the Alberta Heritage Foundation for Medical Research and the Medical Research Council of Canada. DOES MUCOSAL ACID EXPOSURE SENSITIZE ESOPHAGEAL MECHANORECEPTORS? P. Peohini, L. Leite, B. Johnston, D. Castell. The Graduate Hospital, Philadelphia, PA. Objective: To assess the effect of acid infusion on the response of normal subjects to both progressive and sustained intraesophageal balloon distention (IEBO). Methods: 21 healthy volunteers; (mean age 36.4 y (21-60); 7 females, 14 males) underwent IEBD using a 30 co latex balloon 0Nilson-Cook, 14 Fr catheter) placed 5 cm above the manometrically located LES. The balloon was progressively inflated at a rate of 1.4 cc/s and subjects were asked to indicate both the first perception of sensation and onset of pain during inflation, volumes being recorded at both points. The balloon was deflated at the point where a subject indicated pain. Maximum inflation volume was limited to 30 cc. This procedure was then repeated. The balloon was then inflated (1.4 cc/s) to a volume 2 cc lower than the minimal volume which provoked sensation, was kept inflated for a maximum of 60 sac and the time to the onset of sensation and pain recorded. A 0.1 N HCI solution was then infused (8cc/min for 15 minutes) proximal to the balloon. Sensory and pain thresholds were then assessed in the same manner following acid infusion. Results: The correlation coefficients between balloon volumes during first and second inflations, both pre and post acid infusion, was highly significant (p < 0.00001) for both sensation (r = 0.75) and pain (r = 0.84), indicating excellent reproducibility of thresholds to IEBD. Following acid infusion, no significant changes were found in threshold volumes or time to reach thresholds, all values shown in table as median Iran~le): SENSATION PAIN PRE-ACID POST-ACID PRE-AClD POST-ACID PROGRESSIVE 24cc 22cc 29cc 27.5cc INFLATION THRESHOLDS (17-29.51 (12-29) I20.5--30) 120-30) PROLONGED INFLATION 9 sec 5 see 57 sec 35 sec {time to {0-60) (3-60) {0-60) (0-60) symptom) With sustained inflation, 19 (90%) of the 21 subiects experienced sensation and 11 (52%) experienced pain at a volume below their previous threshold. Conclusion: t. Sensation and pain thresholds during IEBD are highly reproducible. 2. Chemoreceptor stimulation by acid infusion does not lead to sensitization of mechanoreceptors using either slow balloon distention or sustained balloon inflation in normal subjects.

983-33 Safety Evaluation of a New Infusion-Perfusion Catheter: Vectocardiographic, Left Ventricular and Coronary Hemodynamic During Local Drug Delivery

Aim of the study was to assess adequacy of myocardial perfusion during deployment of a new intracoronary drug delivery device (D-3. Dispatch tm Scimed). In 22 patients (13 men, 57 ± 10 years) following conventional angioplasty D-3 was inflated at the site of angioplasty. During inflation blood velocity was measured distal to the device at baseline and after drug induced hyperaemia. An angiography was performed to quantify the coronary crosssectional area at the site of Doppler sampling volume to calculate blood-flow. Hemodynamic (high fidelity tip manometer-pigtail in the left ventriclel and vectorcardiography was monitored continuously. During D-3 inflation (mean inflation time 29 ± 8 min) 5 patients had mild chest pain. No significant vectorcardiographic changes were observed during prolonged inflation, Isovolumetric indices of contraction (+dP/dt, V max) and relaxation (–dP/dt, Tau1) at baseline before PTCA and D-3, at the end of PTCA and D-3 inflation, respectively, were as follows: Baseline–PTCA Baseline–D-3 +dP/dt (mmHg/sec) 1313 ± 195 NS 1277 ± 281 1247 ± 218 NS 1332 ± 342 Vmax (sec -1 ) 52 ± 8 NS 54 ± 10 50 ± 8 NS 51 ± 9 –dP/dt (mmHg/sec) 1634 ± 309 *** 1350 ± 374 1522 ± 256 NS 1548 ± 309 Tau1 (msee) 55 ± 10 *** 70 ± 12 60 ± 9 NS 62 ± 8 Mean ± SD. NS = non significant *** p &lt; 0.001 (paired t-test) During intracoronary D-3 inflation basal and hyperaemic flow were 44 ± 31 ml/min and 78 ± 59 ml/min. In conclusion this new infusion catheter allows a nearly normal basal coronary flow with even preserved hyperaemic response during inflation and is subjectively and hemodynamically well tolerated during prolonged inflation permitting sustained local intracoronary drug delivery.

Long-term clinical follow-up of patients successfully treated with a perfusion balloon catheter for coronary angioplasty-induced dissections or abrupt closure

We conclude that prolonged inflations with a perfusion balloon catheter are an effective treatment for severe dissections or abrupt vessel closure complicating elective PTCA, and result in a favorable clinical outcome over the ensuing year. Consequently, they should be considered as first-line therapy when the use of standard balloon equipment fails to achieve an adequate result. As with uncomplicated balloon angioplasty, the major out-of-hospital limitation in the use of a perfusion catheter is the restenosis rate, which in our patients was similar to the control population. Whether other strategies (e.g., stent placement) can provide superior long-term results in patients with actual or threatened abrupt closure requires further investigation.

Pros and cons of perfusion balloons in failed angioplasty.

Prolonged inflation with perfusion balloons is commonly used in failed angioplasty. The objective of this study was to determine the angiographic outcome of 59 consecutive patients treated with prolonged inflation with perfusion balloons as the primary treatment for failed angioplasty. Angiographic success (< 50% stenosis and normal flow) was achieved in 41%. Angiographic success was greater in the left anterior descending coronary artery (67% versus 33% for non-left anterior descending involvement, P = .044) and was less in complex dissections (25% versus 75% for no dissection or simple dissections, P = .025). Angiographic deterioration occurred in 37.5% of the successful group and 77% of the unsuccessful group (P = .002) and was more frequent in the right coronary artery (88% versus 50% for non-right coronary involvement, P = .007) and complex dissections (92% versus 38% for no dissection or simple dissections, P = .0001). Thus, in a group of patients with unsuccessful outcome following conventional balloon angioplasty, success with the perfusion balloon was modest. Furthermore, angiographic deterioration was frequently observed following unsuccessful prolonged inflation.

A randomized comparison of the effects of gradual prolonged versus standard primary balloon inflation on early and late outcome. Results of a multicenter clinical trial. Perfusion Balloon Catheter Study Group.

Observational studies have suggested that prolonged balloon inflation during coronary angioplasty is associated with a high clinical success rate. This randomized clinical trial sought to evaluate the impact of primary gradual and prolonged inflations versus standard short dilatations in patients undergoing elective angioplasty. In phase 1 of the study, patients were randomized to receive two to four standard (1 minute) dilatations or one or two prolonged (15 minutes) dilatations after a perfusion balloon had been placed across a single target lesion. Patients with unsuccessful angiographic appearance after phase 1 dilatations had further dilatations in phase 2. Patients were followed for 6 to 12 months after the procedure. Of 478 patients, 242 received a median of one prolonged dilatation of 15 minutes' duration, and 236 received three dilatations for a median of 1 minute. Patients assigned to prolonged dilatations had a higher success rate (< or = 50% residual visual stenosis) (95% versus 89%; P = .016), less severe residual stenosis by quantitative angiography (median [25th and 75th percentiles], 35% [26%, 42%] versus 38% [30%, 46%]; P = .001), and a lower rate of major dissections (3% versus 9%; P = .003) at the end of phase 1. A total of 114 patients had further dilatations in phase 2-43 in the prolonged arm and 71 in the standard arm. The final procedural success rate was 98% with both primary dilatation strategies, which included additional maneuvers such as prolonged dilatations in the patients randomized to the primary standard dilatation. Overall, 320 of 416 patients (77%) who were discharged after a successful procedure without any in-hospital event (death, myocardial infarction, coronary artery bypass graft surgery, abrupt closure, or repeat angioplasty in target vessel) returned for follow-up angiography. The restenosis rate (> 50% residual visual stenosis) was 44% (95% confidence interval, 37% to 52%) in the prolonged dilatation group and 44% (36% to 52%) in the standard dilatation group. The primary angiographic end point of failure at the end of phase 1, abrupt closure, or restenosis throughout the study period was similar in both groups (prolonged, 51%; standard, 49%; P = .62). The secondary end point of absence of clinical events (death, nonfatal myocardial infarction, coronary artery bypass graft surgery, or repeat angioplasty in target vessel) also was similar (prolonged, 66%; standard, 74%; P = .15). Primary gradual and prolonged dilatations caused less arterial trauma with a modestly larger arterial lumen compared with standard dilatations. This initial improvement in angiographic appearance did not lead to a significant reduction in restenosis or clinical adverse events during follow-up.

Multicenter investigation of coronary stenting to treat acute or threatened closure after percutaneous transluminal coronary angioplasty: Clinical and angiographic outcomes

Objectives. This study reports on the initial experience with the Gianturco-Roubin flexible coronary stent. The immediate and 6-month efficacy of the device and the incidence of the complications of death, myocardial infarction, emergency coronary artery bypass surgery and recurrent ischemic events are presented.Background. Abrupt or threatened vessel closure after coronary angioplasty is associated with increased risk of myocardial infarction, emergency coronary artery bypass graft surgery and in-hospital death. When dissection or prolapse of dilated plaque into the lumen is unresponsive to additional or prolonged balloon catheter inflation, coronary stenting offers a nonsurgical mechanical means to rapidly restore stable vessel geometry and adequate coronary blood flow.Methods. From September 1988 through June 1991, 518 patients underwent attempted coronary stenting with the 20-mm long Gianturco-Roubin coronary stent for acute or threatened vessel closure after angioplasty. In 494 patients, one or more stents were deployed. Thirty-two percent of patients received stents for acute closure and 69% for threatened closure.Results. Successful deployment was achieved in 95.4% of patients. Overall, stenting resulted in an immediate angiographic improvement in the diameter stenosis from 63 ± 25% before stenting to 15 ± 14% after stenting. Emergency coronary artery bypass graft surgery was required in 4.3% (21 of 493 patients). The incidence of in-hospital myocardial infarction (Q wave and non-Q wave) was 5.5% (27 of 493 patients). At 6 months, myocardial infarction was infrequent, occurring in 1.6% (8 of 493 patients). The incidence of in-hospital death was 2.2% (11 of 493 patients). Late death occurred in 7 patients (1.4%) and 34 patients (6.9%) required later bypass graft surgery. Complications included blood loss, primarily from the access site, and subacute thrombosis of the stented vessel in 43 patients (8.7%).Conclusions. The early multicenter experience suggests that this stent is a useful adjunct to coronary angioplasty to prevent or minimize complications associated with flow-limiting coronary artery dissections previously correctable only by surgery. Although this study was not randomized, it demonstrated a high technical success rate and encouraging results with respect to the low incidence of emergency coronary artery bypass graft surgery and myocardial infarction.

Recent changes in the management and outcome of acute closure after percutaneous transluminal coronary angioplasty

The major cause of morbidity and mortality associated with percutaneous transluminal coronary angioplasty (PTCA) is acute closure. This study compared the clinical outcome of 2 groups of patients who experienced acute closure during PTCA. One group was treated during a period when intracoronary stents, laser balloons and perfusion balloons were available for treatment of acute closure (group II). These results were compared with the clinical outcome a group of similar patients who were treated for acute closure during a period that immediately preceded the availability of these devices (group I). One hundred sixty-six patients had acute closure in group I, whereas 156 patients experienced acute closure in group II. Baseline clinical characteristics were similar for both groups. There was no difference in ejection fraction, number of vessels diseased, degree of stenosis or number of vessels attempted between the 2 groups. Patients in group II had more balloon inflations and longer balloon inflation times when compared with patients in group I. Of the 156 patients in group II, 47% were treated with either an intracoronary stent, laser balloon or perfusion balloon. Group II patients had fewer Q-wave myocardial infarctions (9.1 vs 20.3%, p = 0.005). In addition, peak creatine phosphokinase levels (826 ± 1,515 vs 517 ± 1,050, p < 0.01) and mean residual stenosis (40.7 ± 33.2 vs 58.0 ± 34.4%, p < 0.0001) were also lower in group II patients. There was also toss coronary artery bypass grafting during the same admission (38.6 vs 29.5%, p = 0.02) in group II patients. These data suggest that there has been a recent improvement in the clinical outcome of patients with acute closure. This improvement may be related to a more aggressive use of prolonged inflation with standard balloons, in addition to the use of intracoronary stents, laser balloons and perfusion balloons.

Thermal-perfusion balloon coronary angioplasty: In vivo evaluation

The goal of this study was to develop and test a new radio frequency thermal balloon system to allow longer balloon inflations at lower temperature levels than have been used with standard (laser) thermal balloon angioplasty. Radio frequency thermal capabilities were combined with perfusion balloon technology, creating a thermal-perfusion balloon catheter system for prolonged thermal inflations. Twenty-five dogs underwent thermal-perfusion angioplasty at 37°, 60°, or 80° C for 1.5, 5, or 15 minutes with angiographic and morphologic assessments at 24 hours (n = 17) or 4–6 weeks later (n = 8). Treated segments and side branches remained patent. No coronary spasm, occlusive thrombus, or ischemic myocardial infarction occurred. Histologic extent of thermal injury in treated segments was proportional to treatment duration. Thus the thermal-perfusion balloon angioplasty system may be safely applied in canine technologies provides prolonged treatment duration at moderate temperatures without excessive tissue damage.

Excimer laser ablation before autoperfusion balloon inflation: a novel therapeutic approach to high grade stenoses in vessels supplying substantial myocardium at risk.

The utility of a novel approach employing excimer laser ablation to form a channel for subsequent autoperfusion balloon angioplasty is presented. Two important advantages of this strategy are highlighted: (1) applicability to severe stenoses in vessels supplying substantial myocardium at risk and (2) ability to allow prolonged inflation time to minimize procedure related ischemia and optimize revascularization of the heart. We prospectively selected and studied five patients and performed excimer laser coronary angioplasty using either a 1.3 mm or 1.6 mm laser catheter followed by autoperfusion balloon dilatation. Procedural success was documented by a significant reduction in mean percent diameter stenosis from 89 +/- 4% (S.D.) to 53 +/- 4% after laser angioplasty (p < 0.0001) and subsequently to 20 +/- 4% after autoperfusion balloon angioplasty (p < 0.0001). Clinical success was attained and characterized by resolution of anginal symptoms for at least 4 weeks after hospital discharge. There were no major acute complications encountered; however, restenosis has occurred in 2 out of 5 patients. We therefore recommend this novel pre-dilation strategy with excimer laser followed by autoperfusion balloon angioplasty in selected patients with an extensive amount of myocardium at risk.

Coronary angioplasty performed with gradual and prolonged inflation using a perfusion balloon catheter: Procedural success and restenosis rate

The results of routine coronary angioplasty using gradual and prolonged balloon inflation with a perfusion balloon catheter were evaluated. One hundred forty patients were treated with inflation of the balloon to 6 atm over 3 minutes, with a median inflation time of 15 minutes. The procedural success rate (residual stenosis ≤50%) was 99%. In-hospital major complications occurred in five patients (3.6%), with one patient experiencing a periprocedural infarction, three patients requiring bypass surgery for abrupt closure, and one patient dying after elective bypass surgery following previous successful angioplasty of a culprit lesion. The restenosis rate in the 117 patients with angiographic follow-up (87% of those eligible) was 42%. Thus gradual and prolonged inflation using a perfusion balloon catheter resulted in a high procedural success rate and a restenosis rate similar to that reported in large studies of patients treated with standard angioplasty. These results warrant further study using a prospective randomized trial design.

Improved myocardial ischemic response and enhanced collateral circulation with long repetitive coronary occlusion during angioplasty: A prospective study

Objectives. The goal of the study was to evaluate the progressive increase in ischemic threshold with multiple sequential transient coronary occlusions and to assess the role of the collateral circulation in adaptation to ischemia.Background. It has been observed that the duration of balloon inflations during coronary angioplasty can be gradually prolonged during subsequent dilations with a reduction in patient symptoms and diminished ischemic electrocardiographic (ECG) changes. Although the mechanism has not been fully explained, recruitment of coronary collateral circulation induced by repeated coronary occlusion has been reported. The stimuli for recruitment and the natural history of coronary collateral circulation are not understood.Methods. Seventeen patients with isolated stenosis of the left anterior descending coronary artery and a normal left ventricle were enrolled. Angioplasty consisted of five successive prolonged inflations. Sequential changes in clinical, intracoronary ECG and left ventricular indexes of myocardial ischemia were examined. Coronary collateral channels were evaluated during balloon inflations by ipsilateral and contralateral injections of contrast medium and hemodynamically by occlusion pressure.Results. An improved tolerance to myocardial ischemia with repetitive coronary occlusions was demonstrated by a significant reduction of angina, ST segment deviation, left ventricular filling pressure and less impairment of ejection fraction. Left ventricular wall motion abnormalities remained unchanged. Collateral angiographic grade did not change in 7 patients and increased in 10.Conclusions. This study confirms a progressive adaptation of myocardial ischemia to repetitive coronary occlusions and supports the concept that sequential episodes of myocardial ischemia are a stimulating factor for the recruitment of collateral channels in humans. These results also suggest that enhancement of recruitable collateral circulation might be an underlying mechanism of myocardial ischemic preconditioning.

Outcome after prolonged balloon inflations of >20 minutes for initially unsuccessful percutaneous transluminal coronary angioplasty

Prolonged balloon inflation with or without autoperfusion techniques is a common initial approach to major dissection or abrupt occlusion after percutaneous transluminal coronary angioplasty (PTCA). To assess such a strategy in the setting of unsuccessful angioplasty, 40 patients who underwent prolonged balloon inflations of >20 minutes between January and July of 1991 after initially unsuccessful angioplasty were studied. These patients (median age 59 years) underwent PTCA for progressive or unstable angina (16 [40%]), symptomatic or asymptomatic residual stenosis after myocardial infarction (10 [25%]), acute myocardial infarction (3 [8%]), stable angina (3 [8%]), reinfarction (2 [5%]), and other indications (6 [15%]). The significant stenoses were primarily in the proximal and midportions of the right coronary (53%), left anterior descending (30%) and left circumflex (17%) coronary arteries. Before prolonged balloon inflation, the longest single inflation was 11 ± 6 minutes and the total time of all inflations was 17 ± 8 minutes (mean ± standard deviation). Stenosis was reduced from 91 ± 9 to 68 ± 16% before prolonged inflation. After prolonged balloon inflation of 30 ± 9 minutes, the residual stenosis was 47 ± 21% (p = 0.0001 vs value before prolonged inflation). Furthermore, improvements in the appearance of filling defects or dissections, or both, occurred in 19 patients (48%). Procedural success was obtained in 32 of 40 patients (80%). Coronary bypass grafting was performed in 8 patients (20%): 4 after unsuccessful PTCA (3 emergently) and 4 electively after initially successful PTCA. Although 5 patients had creatine kinase-MB elevations >20 IU/liter after the procedure, only 1 sustained a Q-wave myocardial infarction. There were no deaths in the hospital. In summary, prolonged balloon inflations of >20 minutes are successful in 80% of patients in whom initial extensive PTCA attempts were not. Prolonged inflations may thus be desirable before consideration of bypass grafting or stenting.

Hemodynamic and hormonal effects of prolonged anti-G suit inflation in humans.

This study examined the hemodynamic consequences of prolonged lower body positive-pressure application and their relationship to changes in the plasma concentration of the major vasoactive hormones. Six men [36 +/- 2 (SE) yr] underwent 30 min of sitting and then 3 h of 70 degrees head-up tilt. An antigravity suit was applied (60 Torr legs, 30 Torr abdomen) during the last 2 h of tilt. In a similar noninflation experiment, the endocrine responses were measured in the suited subjects tilted for 3 h. Two-dimensional echocardiography was used to calculate ventricular volume and cardiac output. Measurements were made 30 min before and 30 and 90 min after inflation. Immediately after inflation, mean arterial pressure increased by 7 +/- 2 Torr and heart rate decreased by 16 +/- 4 beats/min. Left ventricular end-diastolic volume and systolic volume increased significantly (P less than 0.05) at 30 and 90 min of inflation. Cardiac output increased after 30 min of inflation and returned to the preinflation level at 90 min. Plasma norepinephrine and plasma renin activity were maximally suppressed after 15 and 90 min of inflation, respectively (P less than 0.05). No such hormonal changes occurred during control. Plasma sodium, potassium, and osmolality remained unchanged during both experiments. Thus, prolonged application of lower body positive pressure induces 1) a transient increase in cardiac output and 2) a marked and sustained decrease in plasma norepinephrine and plasma renin activity, which reflect an inflation-induced decrease in sympathetic activity.