The fracture, dislodgement and retrieval of a probe III balloon-on-a-wire catheter

The fracture and dislodgement of an angioplasty device within the coronary arteries is a rare but increasingly noted complication. If the fragment of angioplasty balloon or guidewire is dislodged in a proximal and patent coronary artery, the likelihood of acute embolization which could lead to an acute coronary thrombus and/or myocardial infarction exists. Therefore, the immediate removal of the broken piece of the angioplasty catheter is imperative. A case of unusual fracture and dislodgement of a Probe III Balloon-on-A-Wire catheter and retrieval of the broken piece is reported.

Gastroduodenal intussusception due to Peutz-Jeghers syndrome. A case report

An 18-year-old Chinese male was admitted to our hospital with recurrent abdominal pain, abdominal distension and intermittent non-bilious vomiting of about 2 months standing. A mildly tender mass measuring about 6 x 7 cm was present in the right upper quadrant area, and an abdominal computed tomography scan with enhancement showed a clearly encapsulated mass occupying the right side of the upper intra-abdominal area. Endoscopy revealed two huge cauliflower-like polyps and one small polyp in the stomach, and the biopsy specimens showed hyperplastic polyps. Moreover, multiple pigmentation of the buccal mucosa was also noted. The intra-abdominal mass was found to be a gastroduodenal intussusception following laparotomy. Gastroduodenal intussusception occurring secondarily to Peutz-Jegher syndrome, is a rarely documented condition. Only one case has been reported in Japan during the previous years. We report on another case, and review the literature.

Bilateral hepatic duct decompression via a single percutaneous tract using a 'mother-baby' drainage catheter

Decompression of the right and left hepatic ducts using a 'mother-baby' self-made drainage system via a single percutaneous tract was performed successfully in 15 of 21 patients with benign (n = 4) and malignant (= 17) hilar obstruction. The 'mother-baby' drainage system was composed of an 18 F catheter placed through the right hepatic duct into the distal common bile duct which was designated as the 'mother' catheter, while a second 10 F baby catheter was placed through the first catheter into the left hepatic ducts. This was achieved by a three-stage procedure: (1) percutaneous transhepatic biliary drainage; (2) balloon dilatation of the tract; and (3) intubation of the contralateral hepatic duct and placement of the 'mother-baby' drainage catheters. The mean interval of stent clogging was 5 months, with a range of 2-9 months. In 12 malignant cases, average survival time was 9.8 months. The technique avoided a second percutaneous hepatic puncture in centrally obstructing lesions and afforded bilateral biliary decompression.

Comparison of the causes of late death following aortic and mitral valve replacement. VA Co-operative Study on Valvular Heart Disease

This report examines and compares the causes of late non-surgical death in 146 of 690 (21%) patients undergoing isolated aortic valve replacement (AVR) and in 79 of 273 (29%) patients undergoing mitral valve replacement (MVR) over a five year follow up period. The distribution of valve related, cardiac but not valve-related and non-cardiac deaths was 43%, 23% and 34% respectively for AVR and 65%, 29% and 6% respectively for MVR; the difference between these distributions was statistically significant. The specific causes of valve related deaths included bleeding (11% vs. 5% for MVR vs. AVR), systemic embolization (6% vs. 4% for MVR vs. AVR), endocarditis (14% vs. 8% for MVR vs. AVR), valve regurgitation (8% vs. 5% for MVR vs. AVR) and valve obstruction (3% vs. 5% for MVR vs. AVR). Sudden death (less than one hour from the onset of acute symptoms) accounted for 23% of deaths for MVR and 16% for AVR. The deaths due to congestive heart failure with normal prosthetic valve function were 13% and 8% for MVR and AVR respectively. Non-cardiac causes accounted for only 6% of MVR deaths but 34% of AVR deaths (p < 0.001). There was no significant difference in the late mortality between mechanical and bioprosthetic valves in the aortic position (24% vs. 22%), but the cumulative rate of late deaths was higher in patients with the Björk-Shiley than with the Hancock valve in the mitral position (41% vs. 25%, p < 0.02). In conclusion, about one quarter of patients surviving either aortic or mitral valve replacement died within five years.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative cardiac arrest: a rare complication of T2,3-sympathicotomy for treatment of hyperhidrosis palmaris. Two case reports

Endoscopic surgery, including thoracoscopic sympathicotomy for treatment of hyperhidrosis, is thought to be safe and entail fewer complications as compared with open methods. A total of more than 719 patients with hyperhidrosis have undergone thoracoscopic T2,3-sympathicotomy for treatment of hyperhidrosis at Tainan Municipal Hospital since October 1, 1989. Most of the complications have been minor; however, two of the patients suffered from sudden cardiac arrest at the time when the left T2,3-sympathetic nerve trunk was transected by the thoracoscopic method. Vigorous cardiopulmonary resuscitation was performed and both patients recovered completely without any sequelae. The purpose of this paper was to discuss the possible mechanism of cardiac arrest in thoracoscopic sympathicotomy, and to emphasise this rare but potentially fatal complication in the treatment of hyperhidrosis palmaris.

Percutaneous choledochoscopic biliary tract stone removal: experience in 645 consecutive patients

Our experience in non-operative retrieval of biliary tract stones through PTCS (percutaneous transhepatic cholangioscopy, n = 103) and POC (post-operative choledochoscopy, n = 542) plus the use of Dormia basket and EHL (electrohydraulic lithotripsy) is presented. The results of transhepatic and T-tube routes are compared, with emphasis on the technical difficulties encountered. The success rates were 96% and 97% in POC and PTCS, respectively. No mortality was related to these procedures. Intrahepatic duct angulation and stricture were the factors most often responsible for failure. Postoperative choledochoscopic stone removal is safe and the method of choice for retained biliary tract calculi, while PTCS is highly indicated for those high-risk patients with or without previous biliary surgery. POC and PTCS have, therefore, their own indications and differ in their clinical applications.

Percutaneous transcystic cholangioscopy for combined treatment of gallbladder and bile duct stones

A procedure for percutaneous transcystic cholangioscopy requiring only one percutaneous transhepatic fistulous tract to remove stones located in both the gallbladder and bile ducts is described. The procedure begins with percutaneous transhepatic drainage of the gallbladder or bile duct. Stones in the gallbladder and bile duct can be removed under direct vision on transhepatic cholangioscopy. Larger stones can be fragmented by electrohydraulic lithotripsy before removal. In a preliminary trial the procedure proved to be a feasible method for treatment of 13 patients with both gallbladder and bile duct stones as well as septic cholangitis who either refused operation or were considered poor candidates for surgery. On long-term follow-up (mean period 28 months) stone recurrence was observed in three patients.

[The study of anatomic factors in difficult intubations]

Endotracheal intubation is a common procedure in anesthesia which can usually be accomplished easily. However if the attempt is unexpectedly difficult the patient may be seriously at risk. If all difficult airways can be predicted confidently in the pre-operative period, anesthesiologists can plan the safest and most effective way of managing tracheal intubation. The purpose of this study was to analyze not only the incidence, anatomic factors, immediate complications and management of difficult intubation cases but also the view obtained at laryngoscope which was graded according to the Cormack's and Lehane's description. Patients who received general anesthesia with endotracheal tube within 1 year's period from November 1, 1991 to October 31, 1992 in Show Chwan Memorial Hospital were collected. All difficult intubations were performed by senior anesthesiologists. 3925 patients were intubated, 92 cases were noted to have difficult intubations and their overall incidence were 2.3%. Among the 92 patients, those with 2 anatomic factors (41 patients, 44.6%) represented the majority for patients with difficult intubations. On the other hand, the four most common anatomic factors and their incidences in order of frequency included short neck (48.9%), protruding teeth (38.0%), receding mandible (27.2%) and limited opening mouth (26.1%). According to Cormack's and Lehane's laryngoscopic grading, the results were shown respectively as follow: 4 cases (4.4%) for grade 1;2 cases (2.2%) for grade 2;82 case (89%) for grade 3 and 4 cases (4.4%) for grade 4. We also found that tachycardia/hypertension (70.7%), bleeding (37.0%) and esophageal intubation (33.7%) were the three most frequent immediate complications during difficult intubations.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic and therapeutic interventions in post-laparoscopic cholecystectomy biliary complications

Radiological imaging and therapeutic interventions were performed in eight patients with biliary complications following laparoscopic cholecystectomy. The diagnostic approach and the outcome of the therapeutic procedures were evaluated. Complications observed were bile leakage from the cystic duct stump (n = 2); erroneous identification of the cystic duct leading to common hepatic duct transection (n = 1) and hepatic duct ligation (n = 2); liver abscess (n = 1); and retained common duct stones (n = 2). Diagnostic ultrasonography is capable of detecting the presence of abnormal fluid collection and the diameter of the common duct with or without the presence of a stone, although bile leaks and retained common duct stones can only be demonstrated by either endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. Once a bile leak had been confirmed, therapeutic endoscopic biliary stenting was successfully applied in one patient while the other received percutaneous transhepatic biliary drainage. Definitive diagnosis of retained common duct stone was established by endoscopic retrograde cholangiopancreatography, and immediate endoscopic sphincterotomy with stone extraction was performed. Follow-up radiological imaging was done to determine the effectiveness of the therapeutic procedures applied in each patient. All our patients improved clinically, and further surgical intervention was not needed.

Regional changes in blood flow, extracellular potassium and conduction during myocardial ischemia and reperfusion

OBJECTIVES

We postulated that ventricular arrhythmias may arise from the heterogeneous washout of ischemic metabolites. Our objective was to investigate the distribution of extracellular potassium concentration ([K+]o) during myocardial ischemia and reperfusion and to correlate this distribution with regional differences in myocardial blood flow.

BACKGROUND

Our previous study showed that reperfusion after a brief period of ischemia resulted in heterogeneous reflow of the ischemic myocardium.

METHODS

The changes in regional myocardial blood flow, midmyocardial [K+]o and electrogram duration were quantitated in 14 dogs undergoing 20 min of left anterior descending coronary artery occlusion and 1 min of reperfusion. Regional myocardial blood flow was measured by using 15-microns radioactive microspheres in 1- to 1.5-g full thickness myocardial samples. The [K+]o was measured with intramyocardial K(+)-sensitive electrodes.

RESULTS

During coronary occlusion, the ischemic zone exhibited a reduction in regional blood flow to 0.13 +/- 0.06 ml/g per min and increases in [K+]o to 9.3 +/- 2.6 mmol/liter and electrogram duration to 131.8 +/- 38.6% of control. Heterogeneous reduction in regional blood flow at various sites in the ischemic zone had fair correlations with variable increases in [K+]o (r = -0.70) and electrogram duration (r = -0.75). During min 1 of reperfusion, regional blood flow ranged from two to more than seven times baseline, resulting in a disorganized spatial distribution of perfusion with islands of high and low blood flows. Associated with the heterogeneous early reperfusion regional myocardial blood flow, [K+]o and electrogram duration changed at different rates toward normal. Whereas correlation between regional blood flow and [K+]o or standardized electrogram duration was fair during ischemia, this correlation was poor during early reperfusion.

CONCLUSIONS

Spatial heterogeneity in regional myocardial blood flow during myocardial ischemia and early reperfusion is associated with heterogeneity in [K+]o and electrophysiologic characteristics, which in turn may play an important role in the genesis of arrhythmias arising from the ischemic and reperfused myocardium.

The role of ERCP and therapeutic biliary endoscopy in laparoscopic cholecystectomy

The widespread use of laparoscopic cholecystectomy for the treatment of symptomatic gallstones has been associated with an increased use of diagnostic and therapeutic biliary endoscopy to treat common bile duct stones and postoperative complications. In 250 patients with successful laparoscopic cholecystectomy, 35 were selected for preoperative ERCP evaluation after fitting the criterion of clinical evidence with common bile duct stones (ultrasound and biochemical data). Stones were found in 16 of 35 patients (45.7%). Endoscopic sphincterotomy with stone removal was successfully carried out during the procedure. Laparoscopic cholecystectomy was performed 1 or 2 days after endoscopic sphincterotomy with good result. Only one patient without clinical evidence of common bile duct stones developed postoperative retained stone; he was successfully treated by endoscopic sphincterotomy. Three patients with postoperative bile leakage were successfully treated with endoscopic nasobiliary drainage. Diagnostic and therapeutic ERCP procedures should incorporate the newly developed method of laparoscopic cholecystectomy in order to provide a more safe and minimal invasive therapy.

New approach to management of intraaortic balloon pumps in patients with peripheral vascular disease: case reports of four patients requiring urgent IABP insertion

Four selected cases of emergent IABP insertion in PV patients are presented. After angiographic documentation of critical iliac stenosis, conservative peripheral angioplasty was performed prior to IABP insertion. No patient experienced a peripheral ischemic event associated with IABP use.

Therapeutic embolization of post-cholecystectomy hepatic artery aneurysm

A "sandwich" technique employing steel coils and gelfoam embolization was applied in two cases of hepatic artery aneurysms. Immediate cessation of the bleeding was evident clinically and the post-embolization angiogram showed occlusion of the vascular lesion. Cholecystectomy is one of the most common abdominal operations and it is generally well tolerated, particularly in young and middle-aged patients. Morbidity rates of 5% to 32% and mortality rates of 0.4% to 2.5% have been reported, depending on such factors as age, underlying illness, etc. (1-4). The most frequent complications of cholecystectomy are wound infection, abscess, ductal injury or ligation, and bleeding. This paper describes two cases of hepatic pseudoaneurysm following iatrogenic damage during cholecystectomy which was treated with transarterial embolization.

Effects of intracoronary administration of contrast media on myocardial high-energy phosphate. A comparison of sodium meglumine diatrizoate and iohexol

Myocardial ATP, ADP, and AMP were measured from cardiac biopsy in 11 dogs after intracoronary injection of 6 mL of sodium-meglumine diatrizoate (SMD), iohexol (IOH), or 0.9% sodium chloride (NaCl), and in three of the dogs at baseline before any injection. The ATP at baseline and after SMD, IOH, and 0.9% NaCl were 5.39 +/- 0.41, 3.72 +/- 0.70, 5.52 +/- 0.82, and 5.44 +/- 1.40 mumol/g wet weight, respectively. There were significant differences between SMD and IOH (P less than .02), and between SMD and 0.9% NaCl (P less than .05). The energy charge of SMD was 0.82 +/- 0.08, which differed from 0.89 +/- 0.02 for NaCl or 0.9 +/- 0.05 for baseline (P less than .05), but not from 0.85 +/- 0.04 for IOH. In conclusion, diatrizoate caused significant depletions in ATP stores in comparison with iohexol, but there was no significant difference with respect to energy charge. Nonionic contrast media would be preferable for coronary arteriography in patients whose high-energy stores might be depleted from severe ischemia.

Effects of intracoronary administration of contrast media on coronary hemodynamics in a canine post ischemic reperfusion model

Hemodynamic changes due to intracoronary injections of nonionic contrast medium Omnipaque-350 (OM), ionic dimer Hexabrix (HB), and ionic contrast medium Renografin-76 (R76) were compared at baseline and during reperfusion after a 30-minute left anterior descending coronary artery (LAD) occlusion. In 11 open chest, anesthetized, and atrially paced dogs, 4 ml of either OM, HB, R76, or 0.9% NaCl were injected into the carotid-LAD bypass system. Coronary blood flow (CBF) and coronary vascular resistance (CVR) were measured before, during and after the intracoronary injection. The maximal hyperemic change (in percentage) from the preinjection value of CBF and CVR were calculated. The results at baseline and during reperfusion for CBF were: 104 +/- 14% vs. 85 +/- 10% for OM (NS); 76 +/- 11% vs. 39 +/- 9% for R76 (p less than 0.05); 57 +/- 8% vs. 33 +/- 5% for HB (P less than 0.05); and 30 +/- 7% vs. 9 +/- 4% for 0.9% NaCl (p less than 0.05). Consequently, the hyperemic changes of CVR at baseline and during reperfusion were: -49 +/- 3 vs. -42 +/- 4% for OM (NS); -44 +/- 3% vs. -24 +/- 6% for R76 (p less than 0.01); -36 +/- 3% vs. -24 +/- 4% for HB (p less than 0.05); and -18 +/- 4% vs. -7 +/- 3% for 0.9% NaCl (p less than 0.05). Thus, ischemia and reperfusion significantly dampened the coronary hemodynamic and vascular response to R76, HB, and 0.9% NaCl but not to OM. The preserved coronary vascular reserve with high flow in this canine post-ischemic reperfusion model may explain the advantage of nonionic over ionic contrast media used in emergency coronary angiography following thrombolysis.

A semiinvasive method for articular Colles' fractures

An external fixation device that allows limited motion of the wrist joint without disruption of the anatomic alignment was used for the articular Colles' fractures in this study. From July 1985 to April 1989 during a 45-month period, 87 patients with 90 articular Colles' fractures (three cases with bilateral involvement) were treated with a modified dynamic external skeletal device after a closed reduction in full supination of the forearm. Excellent anatomic reduction near 91% of the sound wrist as well as satisfactory functional results around 90.5% of the sound wrist were gained during the 24-month follow-up period. Forearm muscles exert compression forces on distal radial metaphyseal fractures throughout the healing period. Any procedure or device that cannot provide constant counterforce to the action of forearm muscles during fracture healing will result in the loss of anatomic reduction. Adequate distraction counter-force was provided by an external fixation device that was superior to other conventional methods because of its simple application, low rate of complications, and excellent anatomic and functional results.

Effect of heparin in nonionic contrast media on blood coagulation and its dose response curve

To investigate the local effect of heparin on blood clot formation and partial thromboplastin time (PTT), blood was withdrawn into the catheters filled with iopamidol and heparin at 0, 1, 2, 3, 5, and 10 U per ml concentrations as debubbling. After 30 min incubation, blood clotting was observed in all 8 experiments with heparin concentrations of 0 and 1 U per ml; in 3 of 8 with 2 U per ml; and in none with greater than or equal to 3 U per ml. PTT of blood and contrast mixture in catheters increased significantly when heparin concentrations were increased from 2 to 3 U per ml and reached a level of greater than 110 sec at 5 or more U per ml. Thus, the addition of heparin to nonionic contrast media at concentrations of 5 U per ml may be an easy measure with which to prevent blood clotting and reduce thromboembolic complications during coronary arteriography.

The effect of sodium on hemodynamic changes during coronary angiography with nonionic contrast media

To investigate the effect of sodium on cardiac hemodynamics, sodium chloride was added to nonionic contrast media to a 0.9% concentration and was compared with the standard media iohexol, iopamidol, and ioversol. Left coronary angiography was performed in 10 closed-chest, atrial-paced dogs with 10 ml injections of each preparation in a randomized and blinded fashion. The maximum changes in left ventricular systolic pressure, mean aortic pressure, left ventricular and diastolic pressure, and maximal rise of left ventricular pressure were measured. The left ventricular systolic pressure and mean aortic pressure decreased by 17 +/- 7 mm Hg and by 12 +/- 5 mm Hg with iohexol plus 0.9% NaCl, but only by 5 +/- 4 mm Hg and by 4 +/- 3 mm Hg with iohexol alone (p less than 0.001). The left ventricular and end diastolic pressure increased by 2.2 +/- 0.6 mm Hg with iohexol plus 0.9% NaCl, but did not change with iohexol alone (p less than 0.001). Left ventricular dp/dt decreased by 204 +/- 161 mm Hg/sec with iohexol plus 0.9% NaCl but increased by 392 +/- 122 mm Hg/sec with iohexol alone (p less than 0.001). Similar results were obtained from experiments with iopamidol versus iopamidol plus 0.9% NaCl and ioversol versus ioversol plus 0.9% NaCl. Ioversol plus 5% dextrose or ioversol plus 2.1% choline chloride (isomolar to ioversol plus 0.9% NaCl) produced a significant increase in left ventricular systolic pressure and left ventricular dp/dt (versus ioversol plus 0.9% NaCl, p less than 0.001). Thus, sodium, but not the osmolality or chloride, contributed to the negative inotropic effect of the contrast media.(ABSTRACT TRUNCATED AT 250 WORDS)

Progression of native coronary artery disease at 10 years: insights from a randomized study of medical versus surgical therapy for angina

Repeat coronary angiography was performed in 42 patients 10 years after randomization to medical (n = 21) or surgical (n = 21) therapy for chronic angina. The native coronary arteries were classified into 15 angiographic segments and 3 arterial trunks for analysis of progression of coronary artery disease. The incidence rate of disease progression in coronary segments was 24% and 28% in medically and surgically treated patients, respectively (p = NS). Grafted segments showed a 38% rate of disease progression, which was higher than the 18% rate of for nongrafted segments (p less than 0.001) and the overall rate of 24% for medically treated patients (p less than 0.01). Similarly, 29 (94%) of 31 grafted arteries exhibited disease progression compared with 19 (59%) of 32 nongrafted arteries (p less than 0.01) and 42 (67%) of 63 arteries in medically treated patients (p less than 0.01). In grafted vessels, disease progression occurred more often in arteries proximal (84%) to the anastomosis than in arteries distal (16%) to graft insertion (p less than 0.001). Progression occurred in 46% of proximal segments compared with 23% of distal segments (p less than 0.02). Progression was seen in 23 (55%) of 43 segments with an occluded graft compared with 30 (31%) of 96 segments with a patent graft (p less than 0.02). Ten years after randomization, medically and surgically treated patients showed a comparable rate of disease progression in coronary segments. However, surgical therapy appeared to significantly accelerate atherosclerotic progression in the grafted vessels, especially in the proximal portions. Occluded grafts also correlated with an adverse effect on disease progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac lymphoma associated with superior vena caval syndrome and cardiac tamponade: case history

A sixty-three-year-old patient with malignant histiocytic lymphoma of the heart presented with both superior vena cava syndrome and cardiac tamponade. A two-dimensional echocardiogram showed a large tumor mass in the right atrium and pericardial effusion with right ventricular compression. Superior and inferior vena cavagrams disclosed a lobulated tumor located in the right atrium that extended into and obstructed the superior vena cava. After the pericardial effusion was drained and the diagnosis was established, the patient was irradiated and given chemotherapy with resolution of the tamponade and superior vena cava obstruction.

Use of cyclosporine in the mouse heterotopic heart transplant model

We refined the mouse ear-heart transplant model developed by Fulmer and coworkers and tested cyclosporine as a sole immunosuppressive agent in this model. Three-week-old CBA mice were used as heart recipients, and unsexed newborn BALB/c mice were used as heart donors. The heart grafts were examined for visible pulsations at 10-fold to 20-fold magnification daily for the first 10 days and every other day thereafter. Graft electrocardiograms were also obtained on the same schedule. Preliminary studies had established that a dose of 15 mg/kg/day was the optimal cyclosporine dose in our model. This dose was administered subcutaneously to each of two treatment groups. Group 2 received this dose for the entire 30-day experimental period. Group 3 received this dose for the first 16 days of the experimental period. Group 1 consisted of allografts receiving no immunosuppression. Group 1 grafts showed evidence of initial successful engraftment by day 7; however, by day 13 none of the grafts remained viable. In group 2, 19 of 23 grafts remained viable for the entire experimental period. In group 3, all of the grafts remained viable until day 17 (after day 16 cyclosporine was discontinued) and rapidly lost evidence of viability thereafter. By day 21, none of the grafts in group 3 remained viable. Survival curves for the three groups as determined by electrocardiogram and visible pulsations were constructed, and the differences between the curves were significant (p = 0.001). The results of this study demonstrate the potential usefulness of the ear-heart transplantation model in screening immunosuppressive agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk of thromboembolism during diagnostic and interventional cardiac procedures with nonionic contrast media

To investigate the relationship between clot formation and thromboembolism, canine blood was withdrawn into catheter-syringe or catheter-steerable wire systems containing either contrast medium or normal saline as used in debubbling techniques. The contrast media used were iohexol, iopamidol, ioxaglate, and diatrizoate. Without the use of heparin, after a 30-minute incubation, blood clots were harvested from all catheter-syringe systems except those with diatrizoate and from all catheter-steerable wire systems. Significantly more blood clot was harvested from the catheter-steerable wire system. With use of heparinized blood, no clot was found in any system. Twelve dogs that underwent coronary angiography were divided into two groups; one received heparin (5,000 IU) and the other did not. Thromboembolism occurred in all nonheparinized dogs that underwent angiography with iohexol or iopamidol but not in any other group. The authors found that in a dog model nonionic contrast media are more thrombogenic than ionic contrast media, especially in the catheter-steerable wire system. The blood clot in the catheters is associated with thromboembolism during angiography. The authors maintain that in this setting, blood clotting and thromboembolism with nonionic agents can be eliminated with heparin.

Effects of ionic and nonionic contrast media on bradyarrhythmia during coronary angiography: a comparison of Renografin-76, Hypaque-76, and Isovue-370

Contrast media occasionally produce bradyarrhythmias defined as a 25% decrease in heart rate and/or developing atrioventricular block during coronary angiography. Twelve left coronary angiographies and seven right coronary angiographies were performed with 10 ml of diatrizoate meglumine and diatrizoate sodium (Renografin-76 [R76] or Hypaque [H76]) or iopamidol (Isovue 370 [ISO]) in a blinded randomized fashion. Heart rate decreased significantly from 135 +/- 5 to 120 +/- 5 beats/min (p less than 0.001) with R76, to 127 +/- 7 beats/min (p less than 0.01) with H76, and to 130 +/- 6 beats/min (p less than 0.05) with ISO in left coronary angiographies; more profound decrease was observed in right coronary angiographies from 134 +/- 4 to 87 +/- 18 beats/min (p less than 0.001) with R76, to 99 +/- 14 beats/min (p less than 0.001) with H76, and to 125 +/- 7 beats/min (p less than 0.01) with ISO. In 12 left coronary angiographies bradyarrhythmia was observed in five cases with R76, two with H76, and none with ISO. In seven right coronary angiographies it occurred in six with R76, three with H76, and none with ISO. The differences in the incidence of bradyarrhythmia between R76 and ISO were significant during left and right coronary angiographies (p less than 0.05 and p less than 0.01, respectively). Thus ionic contrast media produced more marked bradyarrhythmias than nonionic contrast media in coronary angiography, especially R76. Right coronary angiography resulted in more profound bradyarrhythmias than left coronary angiographies. This study suggested that nonionic contrast media (ISO) might be preferable to ionic contrast media (R76 or H76) for coronary arteriography.

The mechanism and significance of ventricularization of intracoronary pressure during coronary angiography

Ventricularization of pressure during coronary angiography has been said to identify the presence of left main coronary artery disease, but the hemodynamic features and the mechanism of this process have not been studied. Twenty consecutive patients with ventricularization were identified prospectively in our laboratory. Four patients had a discrete ostial left main stenosis and 16 patients had stenosis of the entire length of the left main coronary artery. The degree of pressure drop upon cannulation of the diseased left main coronary artery was highly variable; the systolic pressure decreased by 9 to 94 mm Hg, and the diastolic pressure decreased by 6 to 60 mm Hg. The morphology of the ventricularized pressure was distinct. It had a presystolic deflection resembling an a wave. The upstroke of this waveform was slower and the downstroke was steeper than that of the aortic pressure. An identical waveform was observed in dogs after partial occlusion of the left main coronary artery with a balloon-tipped catheter. The waveform of the so-called ventricularized pressure is derived from the aortic pressure, which is altered by its transmission across the left main coronary stenosis. The appearance of ventricularization is an important clue to the presence of left main coronary artery disease.