Balloon Removal Research Articles

New endoscopic technique for intragastric balloon removal

New endoscopic technique for intragastric balloon removal

Postmarket Surveillance for Drug-Eluting Coronary Stents

The development and introduction of new medical devices have radically changed the practice of medicine. No area of medicine has been affected more than cardiology, with new devices facilitating the effective treatment of coronary artery disease (percutaneous coronary interventions [PCIs]/stents), valvular heart disease (mechanical and bioprosthetic valves), and electrophysiological disorders (pacemakers and automatic implantable cardiodefibrillators). In addition to fueling the growth of the medical device industry, this explosion of technology has driven the development of new medical subspecialties, eg, interventional cardiology and electrophysiology. Other areas of medicine, including orthopedics and general surgery, have witnessed similar transformations. The current regulatory pathway for a significant-risk first-in-class medical device is typically a long, expensive, and risky process, culminating in a pivotal trial designed to demonstrate safety and efficacy. The pivotal trial phase is typically the most time-consuming and costly phase of the process. In the United States, medical devices are regulated by the Center for Devices and Radiological Health at the Food and Drug Administration (FDA), which has been charged by Congress to seek the “least burdensome means” when determining the scope of data required to evaluate the safety and efficacy necessary for device approval.1 Thus, pivotal trials by intention are designed to select patient cohorts most likely to demonstrate procedural benefit while limiting patient/study subject risk within the shortest time frame that can provide meaningful data. The realities of logistics, time, and resources limit the size and duration of most new device trials to 800 to 1500 patients, limiting the power of these trials to detect events with an occurrence rate of <1%. Furthermore, pivotal trials are conducted by the most experienced physician operators at medical centers with sufficient patient volume and research infrastructure to recruit and conduct clinical studies. Some have questioned whether results obtained under these settings from such …

Relative increase in lung volume in fetuses with congenital diaphragmatic hernia treated by fetoscopic endoluminal tracheal occlusion (FETO)

Relative increase in lung volume in fetuses with congenital diaphragmatic hernia treated by fetoscopic endoluminal tracheal occlusion (FETO)

BioEnterics Intragastric Balloon: The Italian Experience with 2,515 Patients

The temporary use of the BioEnterics Intragastric Balloon (BIB) in morbidly obesity is increasing worldwide. The aim of this study is the evaluation of the efficacy of this device in a large population, in terms of weight loss and its influence on co-morbidities. Data were retrospectively recruited from the data-base of the Italian Collaborative Study Group for Lap-Band and BIB (GILB). After diagnostic endoscopy, the BIB was positioned and was filled with saline (500-700 ml) and methylene blue (10 ml). Patients were discharged with diet counselling ( approximately 1000 Kcal) and medical therapy. The BIB was removed after 6 months. Positioning and removal were performed under conscious or unconscious sedation. Mortality, complications, BMI, %EWL, BMI loss and co-morbidities were evaluated. From May 2000 to September 2004, 2,515 patients underwent BIB (722M/1,793F; mean age 38.9+/-14.7, range 12-71; mean BMI 44.4+/-7.8 kg/m(2) ; range 28.0-79.1; and mean excess weight 59.5+/-29.8 kg, range 16-210). BIB positioning was uncomplicated in all but two cases (0.08%) with acute gastric dilation treated conservatively. Overall complication rate was 70/2,515 (2.8%). Gastric perforation occurred in 5 patients (0.19%), 4 of whom had undergone previous gastric surgery: 2 died and 2 were successfully treated by laparoscopic repair after balloon removal. 19 gastric obstructions (0.76%) presented in the first week after positioning and were successfully treated by balloon removal. Balloon rupture (n=9; 0.36%) was not prevalent within any particular period of BIB treatment, and was also treated by BIB removal. Esophagitis (n=32; 1.27%) and gastric ulcer (n=5; 0.2%) presented in patients without a history of peptic disease and were treated conservatively by drugs. Preoperative co-morbidities were diagnosed in 1,394/2,471 patients (56.4%); these resolved in 617/1,394 (44.3%), improved (less pharmacological dosage or shift to other therapies) in 625/1,394 (44.8%), and were unchanged in 152/1,394 (10.9%). After 6 months, mean BMI was 35.4+/-11.8 kg/m(2) (range 24-73) and %EWL was 33.9+/-18.7 (range 0-87). BMI loss was 4.9+/-12.7 kg/m(2) (range 0-25). BIB is an effective procedure with satisfactory weight loss and improvement in co-morbidities after 6 months. Previous gastric surgery is a contraindication to BIB placement.

Obstructive Sleep Apnea Syndrome in Morbid Obesity: Effects of Intragastric Balloon

In obese patients, obstructive sleep apnea syndrome (OSAS) is attributed to a reduction in pharyngeal cross-sectional area due to peripharyngeal fat deposition. The effect of weight loss on the size of the upper airways of obese subjects is still unknown. We analyzed the pharyngeal cross-sectional area before and after weight loss in morbidly obese patients with OSAS.A group of 17 middle-aged, morbidly obese men was evaluated by anthropometry and cardiorespiratory sleep studies before and after weight loss obtained by insertion of an intragastric balloon. The pharyngeal cross-sectional area was measured by acoustic pharyngometry.The mean (+/- SD) body mass index was 55.8 +/- 9.9 kg/m2 at baseline and 48.6 +/- 11.2 kg/m2 at the time of balloon removal (6 months after insertion) [p < 0.001]. At baseline, patients had visceral obesity, large necks, and severe OSAS. Weight loss was associated with a significant mean reduction of waist circumference (156.4 +/- 17.6 vs 136.7 +/- 18.4 cm, respectively; p < 0.001), sagittal abdominal diameter (37.8 +/- 3.0 vs 32.3 +/- 4.0 cm, respectively; p < 0.001), and neck circumference (51.1 +/- 3.7 vs 47.9 +/- 4.3 cm, respectively; p < 0.001). Moreover, weight loss induced a nearly complete resolution of OSAS (apnea-hypopnea index, 52.1 +/- 14.9 vs 14.0 +/- 12.4 events/h, respectively; p < 0.001). At baseline, obese patients had significantly lower pharyngeal cross-sectional areas compared to a group of 20 nonobese male control subjects, both in the upright and supine position, at different levels of the pharynx. In obese patients, the weight loss induced by the positioning of the intragastric balloon was associated with an increase in the size of the upper airway passage. After weight loss, both the mean pharyngeal cross-sectional area and the area at glottis level were still lower in obese subjects than in nonobese subjects; however, the pharyngeal cross-sectional area at the oropharyngeal junction was similar in the two groups.Morbidly obese men with OSAS have a reduced pharyngeal cross-sectional area. A weight reduction of about 15% of baseline body weight may substantially increase the pharyngeal cross-sectional area and substantially improve the severity of OSAS in morbidly obese subjects with sleep apnea.

Effects of Intragastric Balloon on Gastric Emptying and Plasma Ghrelin Levels in Non-morbid Obese Patients

Intragastric balloons have been proposed to induce weight loss in obese subjects. The consequences of the balloon on gastric physiology remain poorly studied. We studied the influence of an intragastric balloon on gastric emptying and ghrelin secretion in non-morbid obese patients. 17 patients were included in the study, with mean BMI of 34.4 (range 30.1-40.0). The balloon was inserted under general anaesthesia and endoscopic control, inflated with 600 ml saline, and removed 6 months later. Body weight and gastric emptying (13C-octanoic acid breath test) were monitored while the balloon was in place and 1 month after removal. Ghrelin levels were measured just before balloon insertion and removal. Mean weight loss was 8.7 kg (range 0-21). Gastric emptying rates were significantly decreased with the balloon in place, and returned to pre-implantation values after balloon removal. Plasma ghrelin levels were significantly decreased (95% CI: -3.8 to -20.7 ng/ml), despite concomitant weight loss. Weight reduction was not correlated to the effect of the balloon on gastric emptying, but was significantly correlated to the ghrelin variations (r=0.668, 95% CI: 0.212-0.885). Gastric emptying rates and plasma ghrelin levels are decreased in the presence of intragastric balloon. Weight loss induced by the intragastric balloon is related to ghrelin variations, but not to gastric emptying. Ghrelin inhibition may explain part of the effect of the balloon on satiety.

External Femorofemoral Bypass to Relieve Acute Leg Ischemia during Circulatory Assist

The development of limb ischemia in patients who are dependent on an intra-aortic balloon pump (IABP) and/or extracorporeal membrane oxygenation (ECMO) is a serious problem. We used external femorofemoral bypass grafting at the bedside as a salvage procedure in two such patients with effective reversal of ischemia, although both died of cardiac complications. This procedure can be considered in patients who are severely coagulopathic and are dependent on IABP and/or ECMO, in whom the graft removal would be considered at the time of balloon removal.

The ex utero intrapartum treatment procedure: looking back at the EXIT

Purpose The ex utero intrapartum treatment (EXIT) procedure was developed originally for management of airway obstruction after fetal surgery, and indications have continued to expand for a variety of fetal anomalies. The authors review their single-institution experience with EXIT. Methods Retrospective review of all patients who underwent an EXIT procedure from 1993 to 2003 (n = 52) was performed. Variables evaluated include indication for EXIT, gender, gestational age at EXIT, birth weight, maternal blood loss, operative complications, operative time, and survival rate. Technique, personnel, and anesthesic management were reviewed. Results Long-term follow-up was available for all patients. Fifty-one of 52 patients were born alive; currently, 27 of 52 patients (52%) are alive. All deaths have been in patients with congenital diaphragmatic hernia. Forty-five patients underwent EXIT for reversal of tracheal occlusion for congenital diaphragmatic hernia. Of these patients, 30 underwent tracheal clip removal. Two patients had repair of tracheal injury from clipping at EXIT. Fifteen patients underwent bronchoscopy and tracheal balloon removal. Five patients underwent EXIT procedure for neck masses. Tracheostomy was performed in 3 of these patients. One patient was intubated successfully, and 1 patient underwent resection of the neck mass while on placental support. Two patients underwent EXIT procedure and tracheostomy for congenital high-airway obstruction syndrome. Average gestational age at delivery was 31.95 ± 2.55 weeks. Average birth weight was 1,895 ± 653 g. Average maternal blood loss was 970 ± 510 mL. Average operating time on placental support was 45 ± 25 minutes with a maximum of 150 minutes. Conclusions EXIT procedures can be performed with minimal maternal morbidity and with good outcomes. It is an excellent strategy for establishing an airway in a controlled manner, avoiding “crash” intubation or tracheostomy. Longer procedures on placental support allowing for definitive management of neck masses and airway obstruction have been realized. EXIT procedures have evolved from an adjunct to fetal surgery to a potentially life-saving procedure in fetuses with airway compromise at birth.

In-Hospital Complications of Percutaneous Intraaortic Balloon Counterpulsation

Complications related to intraaortic balloon counterpulsation pumping (IABP) remain a problem despite the development of small caliber balloon catheter shafts and introducer sheaths. The authors report their experience in counterpulsation-related complications of 201 consecutive patients who underwent 212 percutaneous counterpulsation balloon insertions from June 1989 to June 1996 by use of balloons with 8-9.5 French shafts. Of these, 82% were men and 36 (18%) were women, with a mean age of 61 +/-12 years. Indications for counterpulsation were acute myocardial infarction (AMI) (67%), severe left ventricular failure without AMI (20%), dilated cardiomyopathy (4%), unstable angina (3%), high-risk supported percutaneous coronary angioplasty (2%), and others (4%). IABP was instituted at the bedside in the intensive care unit in 82 patients (39%) and in the catheterization laboratory in 130 (61%). Median duration of counterpulsation was 48 hours (range 30 minutes to 25 days) with successful weaning from counterpulsation in 70% (148 of 212) of procedures. Overall in-hospital mortality rate was 45% (90 of 201). The overall complication rate was 22/212 (10.4%). Major complications were present in 10/212 procedures (4.7%): 6 patients with limb ischemia (1 death directly attributed to this complication, 1 with associated septicemia and limb amputation, 3 requiring surgical thromboembolectomy, and 1 with persistent limb ischemia treated medically until his death caused by intractable left ventricular failure), 2 with important bleeding (1 fatal despite vascular surgical repair and 1 requiring blood transfusion) and 2 with balloon rupture requiring vascular surgery. Minor complications were present in 12 procedures (5.7%), 6 with limb ischemia, 3 with local bleeding, and 3 with catheter dysfunction. All of these resolved after balloon removal and required no further intervention. When limb ischemia did develop it occurred after a median delay of 24 hours following balloon insertion (range 2 to 98 hours). The only predictor of limb ischemia among baseline clinical and procedure-related variables was an age greater than 60 years. Compared with previous recent studies, the rate of complications observed in this study performed with small balloon catheters was acceptably low. Limb ischemia was the most frequent complication, often occurred early, and required further intervention in half the cases.

Gastro-oesophageal Reflux in Obese Subjects: Influence of Overweight, Weight Loss and Chronic Gastric Balloon Distension

Background: Gastro-oesophageal reflux is an obesity-related health risk assumed to improve after weight loss. Prolonged intragastric balloon distension might oppose this. The purpose of the study was to investigate the prevalence of gastro-oesophageal reflux in untreated obese subjects and to study the consequences of weight loss with or without intragastric balloon treatment. Methods: Patients participating in a randomized double-blind, sham-controlled trial received balloon or sham treatment for the first 13 weeks. Thereafter, all subjects received a balloon for the remaining year. Twenty-four-hour pH recordings were made at the start, after 13 weeks of balloon or sham treatment, after 26 and 52 weeks of balloon treatment and 13 weeks after balloon removal. Results: Group-wise, pH data of 42 untreated patients (BMI 43.4 kg/m 2 ) were highly abnormal. On an individual level, 22 subjects (52%) had some evidence of reflux, 17 patients (40%) showed pathological total reflux times and 8 (19%) had combined total, upright and supine reflux with grade B reflux oesophagitis in only one patient. Albeit poorly, oesophageal acid exposure was related to body weight and visceral fat distribution. A reduction in acid reflux was observed in sham-treated weight-losing subjects, whereas in balloon-treated subjects supine reflux and duration of the longest reflux increased. In the second 13-week period, the initially improved pH values worsened by balloon placement in sham-treated subjects. Values in balloon-balloon-treated subjects stabilized. After 52 weeks, acid reflux levelled off at pretreatment values and further improved after balloon removal. At these times, decreased visceral fat masses correlated significantly with diminished oesophageal exposure to acid. Conclusions: Obesity predisposed to gastro-oesophageal reflux. Body weight loss and, strikingly, visceral fat loss resulted in improved reflux parameters. Adverse effects on acid reflux by gastric balloon distension wore off over time.

Intragastric balloon in obese patients.

Since March 1998, 143 BioEnterics Intragastric Balloons (BIB) were placed in 132 obese and morbidly obese patients, to study the clinical possibilities of a new system, both from the point of view of the materials used and the application method. 36 patients were male and 96 female; mean age was 43 years (21-70); mean weight was 115.4 kg (67-229), and mean BMI was 41.0 (29-81). 8 patients were affected by severe respiratory insufficiency. We placed and removed the balloon endoscopically under conscious sedation or general anesthesia. BIB was removed in the majority of patients 4 months after insertion. The patients were given a balanced diet of 800-1000 kcal/day; follow-up involved a monthly check-up (routine blood tests, weight control) and a visit every 15 days with the dietitian. Mean weight loss was 14.4 kg; mean reduction in BMI was 5.2. Weight loss was much better in males. The weight loss produced an improvement of the complications associated with the obesity. Complications observed were: balloon intolerance (9 early removals), 1 balloon deflated and passed, 2 cases of gastric ulcer at balloon removal. The most correct indications for BIB should be: extremely obese patients (BMI>40) in preparation for a bariatric operation; obese patients with BMI 30-35 with a chronic disease otherwise unresolved; patients with BMI<30 in a multidisciplinary approach.

CT-Guided Decompression of a Foreign Body Obstructing the Small Bowel: Case Reports

Hooker G. D. (2000). Clinical Radiology55, 153–54.

Preparation of extremely obese patients for laparoscopic gastric banding by gastric-balloon therapy.

In super, super obese patients (body mass index [BMI] >60), especially those with extreme intra-abdominal fat deposition, the technical difficulties in laparoscopic procedures increase. The purpose of this study was to evaluate whether gastric balloon therapy (GBT) can improve the operative conditions for laparoscopic adjustable gastric banding (LAGB) in extremely obese patients. From April 1995 to August 1998, 196 LAGBs were performed. In 15 patients (7 female and 8 male), median age 38.8 years (range 17-54), who had been selected as suitable candidates for bariatric surgery, preoperative GBT was studied. Fourteen patients were extremely obese (BMI 60.2 kg/m2 [range 58-72]). One 17-year-old boy with BMI 46.6 kg/m2 was also treated. The Bioenterics Intragastric Balloon (BIB) was used. The placement, the volume modification, and the removal of the BIB were performed endoscopically. Close follow-up was possible in 14 patients. After balloon removal, 13 patients underwent LAGB. In 14 of 15 cases, GBT was successful. There was only one ballon dysfunction. The mean weight loss was 18.1 kg, and the median duration of balloon therapy was 16.8 weeks. After balloon removal, body weight started to increase. In our experience, the gastric balloon can improve the conditions for laparoscopic surgery in super and in super, super obese patients. There was no conversion to open surgery. The effect of weight loss is much less than immediately after LAGB. However, after failure of all conservative treatments to reduce the preoperative body weight, the GBT seems to be the last possibility.

Embolotherapy of aneurysms under temporary balloon occlusion of the neck. In vitro study of a newly designed eccentric balloon catheter.

To test embolotherapy of aneurysms in an in vitro model using standard and specially designed eccentric occlusion balloon catheters for simultaneous delivery of the embolization agent and occlusion of the neck of the aneurysm. Two different in vitro set-ups were used: a bifurcational aneurysm and an aneurysm with a straight parent vessel segment, both made from elastic silicone and glass. Each model was exposed to a pulsating perfusion. The effluent was collected and filtered. For the bifurcational aneurysms, commercially available occlusion balloon catheters with a working channel exiting at the tip were used. For the aneurysms with straight parent vessel, the catheters were modified so that the balloon opened eccentrically. The working channel of the catheter led to a side hole, which was located where the balloon membrane was fixed to the catheter shaft. The aneurysms were filled with coils, ethibloc, or hydrogel, and with coils combined with ethibloc or hydrogel, while the expanded balloon occluded the neck. Embolization of aneurysms under balloon occlusion of the neck was technically feasible with the catheter devices. Dense packing with coils was possible in all cases without coil dislocation, but unfilled interspaces remained between the coil wires. Best filling was achieved with ethibloc or hydrogel alone or in combination with coils. During the filling procedure, there was no distal embolization of the liquid agents. However, after balloon deflation, considerable amounts of hydrogel or ethibloc were washed out from the aneurysm. The results suggest that balloon occlusion of the neck allows compact filling and minimizes the risk of dislocation in coil embolotherapy of aneurysms. In nonbifurcational aneurysms, the eccentric balloon catheter seems to be suitable for this treatment concept. Although liquid agents may be safely delivered into the aneurysm under balloon protection, their considerable washout rate after balloon removal requires further refinements of the technique before clinical application is advisable.

Hemostatic Assessment of Patients Undergoing lntraaortic Balloon Pump Therapy

Patients undergoing intraaortic balloon pump (IABP) therapy are at risk for developing coagulopathies due to the adverse effects of prolonged exposure of the synthetic surface of the polyurethane balloon to blood components. Hemorrhagic risk has been attributed to a number of factors including thrombocytopenia, vascular injury, and/or platelet degranulation which increase the potential of receiving autogeneic blood transfusions. The present study is a prospective evaluation of coagulation using a viscoelastic monitor (Thrombelastograph- TEG) that measures functional aspects of clot development and stabilization in patients being treated with IABP therapy. Following Institutional Review Board approval, six patients undergoing IABP therapy for hemodynamic instability were enrolled in this study. Blood samples were taken prior to balloon insertion, at 8, 16, 24, 48, 72, and 96 hours on IABP therapy, and 24 hours following the removal of the balloon when applicable. Samples were incubated with heparinase to degrade heparin and TEG profiles were subsequently determined in duplicate. Measured parameters on the TEG included Rtime, K-time, maximum amplitude, alpha angle, and lysis at 30 and 60 minutes with calculation of the TEG index. Mortality was 33% following IABP discontinuation. Transfusion of packed red blood cells occurred in 50% of the patients during their balloon pump therapy. Patients demonstrated a significant deviance in fibrinolytic potential from pre-IABP lysis (1.6% ± 1.8) at both 24 hours (18.8% ± 22.9) and 48 hours (21.9% ± 28.5) of therapy (p&lt;0.05) which returned to baseline shortly after balloon removal. Activation of coagulation factors appeared evident by a steadily increasing alpha angle from pre-IABP data (31.1 ± 9.2) throughout the duration of therapy and 24 hour recovery (53 ± 14; p&lt;.005), and by a steadily trending increase in the TEG index pre-IABP (.251 ± 1.4) to post-IABP (2.6 ± 1.7; p&lt;0.05). The results indicate that IABP therapy induces an increase in fibrinolytic potential at 24 to 48 hours of balloon pump therapy with a paradoxical trend toward increased coagulability, potentially predisposing the patient to hemorrhagic risk.

Ripening of the Unfavorable Cervix With Extraamniotic Catheter Balloon

The use of an extraamniotic catheter balloon, inflated above the internal cervical os, has been advocated as a nonpharmacological, mechanical method of cervical ripening before induction of labor. Additional measures may include applying traction on the catheter, or the infusion of normal saline (1 ml/min) via the catheter's port into the extraamniotic space. The results of catheter balloon cervical ripening are reviewed from 13 published reports and a departmental series of 190 pregnancies with unfavorable cervix, encompassing nearly 1000 patients. A mean change in cervical score of at least 3 points, was noted in most studies after balloon expulsion or removal. The present series and other studies suggest that oxytocin use for induction and/or augmentation of labor is increased after balloon ripening, compared with its use in spontaneous labor or after cervical ripening by prostaglandins. In 11 studies, catheter balloon ripening was compared with cervical ripening by other mechanical, or pharmacological (i.e., oxytocin or prostaglandins) methods. Of these, eight were prospective and randomized-controlled and three were case-controlled studies. It is suggested that ripening efficacy by catheter balloon is similar, or better, than other methods; but there is no significant difference in the mode of delivery or perinatal outcome. This review also suggests that cervical ripening with extraamniotic catheter balloon has the advantages of simplicity, low cost, reversibility, and lack of systemic or serious side effects.

Intraaortic balloon entrapment

A review of intraaortic balloon pump use at the University of Miami/Jackson Memorial Medical Center over the past 21 years identified 2 cases where a balloon was found to be entrapped. The balloon catheters had been in place for approximately 10 days when this complication occurred. The retained balloons were torn, filled with clotted blood, and impacted in the vasculature. In our first case, forceful removal of the intraaortic balloon was complicated by unintentional extraction of the external iliac and common femoral arteries. In the second case, clot within the balloon was dissolved with tissue plasminogen activator injected into the drive lumen of the catheter before removal. The prevention and management of this rare but serious complication of intraaortic balloon pumping is reviewed.

Technical failure of biliary metal stent deployment in a series of 116 applications.

Biliary metal stents are thought to offer improved long-term palliation of malignant biliary obstruction due to a lower incidence of migration and clogging. Placement of these stents is technically more complicated than that of plastic endoprostheses and requires two experienced physicians. We report the incidence and reasons for apparent malfunction of expandable metal stent deployment (Wallstents and Strecker stents). In 116 applications of 82 Wallstents (endoscopic approach: n = 33, transhepatic approach: n = 49), we observed 19 cases of stent malfunction due to technical problems of stent delivery. In 13 cases (15.8%), the restraining membrane of the Wallstent could not be retracted sufficiently to deliver the stent. There were 6 (17.6%) failures in 34 cases of Strecker stent deployment. In 3 cases, we noted difficult balloon removal, including avulsion of the balloon catheter shaft within the endoscope during attempted balloon removal in one case. In one case, the Strecker stent could only be released partially, requiring subsequent endoscopic extraction. In two patients, only partial expansion of one end of the Strecker stent could be achieved. Given the significant malfunction rate of expandable metal stents during stent delivery, further improvements in the delivery system of the metal stents are required.

Intraaortic Balloon Pump Entrapment

Catheter entrapment is a rare complication of intraaortic balloon counterpulsation caused by the formation of hard blood clot within the balloon itself. We present two cases of intraaortic balloon pump entrapment seen at the University Hospital, Boston. This phenomenon usually presents as a limb threatening vascular emergency. The entrapped catheter becomes stuck fast within the iliac system during withdrawal of the device, occluding arterial flow at that level. The etiology of this phenomenon, and a proposed management scheme is discussed. Preoperative radiographic determination of the level of entrapment may be necessary. We feel it is necessary to control the abdominal aorta prior to removal of an entrapped intraaortic balloon.

Angiographic demonstration of hyperconstriction induced by serotonin and aggregating platelets in porcine coronary arteries with regenerated endothelium

In isolated porcine coronary arteries, the endothelium inhibits the contractions induced by serotonin and aggregating platelets. This effect is reduced by regeneration after balloon denudation. The present study was designed to examine whether those in vitro observations could be reproduced in vivo. Sixteen male Yorkshire pigs underwent balloon removal of the endothelium from either the left anterior descending (n = 9) or left circumflex (n = 7) coronary artery. An angiographic study was performed before and 4 weeks after endothelial denudation; in the latter condition the presence of a full endothelial lining was confirmed histoiogically.Before endothelial denudation, intracoronary injection of serotonin (10 μg/kg) caused only mild constriction in both arteries. However, 4 weeks after the denudation, intracoronary serotonin repeatedly caused marked hyperconstriction in the previously denuded artery compared with the control coronary artery. Intracoronary injection of aggregating platelets stimulated by collagen caused constriction in the previously-denuded artery but not in the control artery. The hyperconstriction induced by serotonin and aggregating platelets was inhibited by intravenous injection of ketanserin (a 5-HT2-serotonergic blocker).These data indicate that 1) the normal eadoihelium blunts the coronary vasoconstriction induced by serotonin and aggregating platelets in vivo, and 2) the inhibitory effect of the endothelium is reduced after regeneration, allowing coronary hyperconstriction or vasospasin, or both.