Prevalence and predictors of renal artery stenosis in Chinese patients with coronary artery disease.

BACKGROUND: Ischaemic nephropathy is currently a major public health issue in atherosclerotic populations. Although atherosclerotic cardiovascular disease in Asia has reached epidemic proportions over the last two decades, there is little published data on the prevalence of atherosclerotic renal artery stenosis (ARAS) in Oriental subjects. Because ARAS may be clinically silent until end-stage renal failure sets in, it is important to identify patients with significant but clinically unsuspected ARAS. ARAS and coronary artery disease (CAD) often coexist. AIMS: The purpose of the present study was to evaluate the prevalence and predictors of ARAS among Chinese patients with CAD. METHODS: A total of 230 consecutive Chinese patients with CAD confirmed by coronary angiography underwent an abdominal aortogram in the same sitting to screen for ARAS. Patient demographics and comorbidities were analysed for any association with ARAS. RESULTS: A total of 34 (14.8%) patients was found to have significant ARAS. Age and multivessel CAD were independent predictors of ARAS. Hypertension, renal insufficiency, extracranial cerebrovascular disease and female gender were also associated with a higher risk of ARAS but did not independently predict ARAS. CONCLUSION: Clinically silent yet angiographically significant ARAS is common among CAD patients. The prevalence and predictors of ARAS among Chinese patients with CAD are similar to those reported for Caucasian subjects. Underlying ARAS should be suspected in CAD patients with such comorbidities as hypertension, renal insufficiency, extracranial cerebrovascular disease, and more so in the elderly and those with multivessel disease.

Percutaneous transluminal stenting in patients with carotid artery stenosis.

OBJECTIVE: To assess the efficacy and safety of percutaneous transluminal stenting for patients with carotid artery stenosis. METHODS: Selective percutaneous transluminal stenting was performed for patients with symptomatic carotid artery stenosis (luminal narrowing > or = 70%). Success rates and complications associated with the procedures were observed. During six months of follow-up, both recurrent symptom and restenosis rates were recorded. RESULTS: There were 17 bifurcating lesions among 27 stenoses in 26 patients, of whom 18 had concomitant coronary artery diseases. The acute procedural success rate was 96.3% (26/27), and the degree of stenosis was reduced from 88.6% +/- 8.9% (range 70-100) to 0.4% +/- 2.0% (range 0-10). Six patients developed severe bradycardia and hypotension, and 3 experienced transient loss of consciousness during balloon dilatation. During hospitalization, 2 patients experienced loss of consciousness and convulsion, respectively, due to hyperperfusion, and both recovered 12 hours later. There were 2 minor stroke cases (7.4%) but no cases of major stroke or death. At the 6-month follow-up, there were no cases of TIA or new onset of stroke. There was no restenosis detected in 16 cases using angiography and in 10 cases using MRI in 6 to 16 months of follow-up. CONCLUSIONS: Percutaneous transluminal stenting for patients with carotid artery stenosis has a high procedural success rate with few and acceptable complications. Few patients suffered from recurrent symptoms or showed restenosis in long-term follow-up.

Intracarotid abciximab injection to abort impending ischemic stroke during carotid angioplasty.

BACKGROUND: Abciximab, a platelet glycoprotein IIb/IIIa receptor antagonist, prevents ischemic complications during percutaneous transluminal coronary angioplasty and was recently shown to open occluded vessels in patients with acute myocardial infarction when used alone or in combination with other thrombolytic agents. In an animal model of arterial thrombosis, abciximab was found to be safe and effective for the prevention of carotid artery thrombosis. However, the safety and efficacy of abciximab in the treatment of acute ischemic cerebrovascular events is unknown at present. CASE DESCRIPTION: We describe 3 patients who experienced ischemic cerebrovascular events with symptoms involving the middle cerebral artery territory while undergoing percutaneous angioplasty and stenting to their internal carotid arteries. Abciximab was administered to each patient within 10 min of symptom onset as a bolus (0.25 mg/kg) into the ipsilateral common carotid artery followed by continuous intravenous infusion (9 microg/min) for 12 h. All patients' symptoms resolved completely (by 25 min, 40 min and 5 h, respectively) with no further neurological complications. CONCLUSIONS: Our preliminary observation suggests that abciximab may improve neurological outcome following middle cerebral artery ischemic events associated with carotid angioplasty and stenting. Large prospective studies are warranted to establish the safety and efficacy of abciximab in acute ischemic stroke, either as a primary treatment modality or an adjunct to carotid angioplasty and stenting.

ChoICE PT wire for recanalization of chronically occluded coronary arteries: multiple wires in one?

Percutaneous transluminal coronary angioplasty (PTCA) of chronic total occlusions may be technically difficult and the success rate is limited despite increasing operator experience and improvements in PTCA hardware. The number of guidewires required to cross totally occluded lesions is higher than that for stenotic lesions. The ChoICE polymer-tip (PT) wire (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) is a relatively new stainless-steel core wire with a hydrophilic-coated polyurethane tip. Though never described in the literature, we found that the distal 4 cm of the wire can be cut and reshaped according to the operator's needs. Thus, instead of reshaping a kinked tip or using another new wire, the former being time-consuming and the latter expensive, one can simply cut off the kinked tip and start again with a "new wire." As the tip is resected, the wire becomes progressively more "intermediate-like" and "standard-like." We report our experience with the ChoICE PT wire in 50 consecutive cases of chronic total occlusions. The cumulative crossing success rates were 13/50 (26%) before any resections, 24/50 (48%) after 1 resection, 41/50 (82%) after 2 resections and 42/50 (84%) after 3 resections. There were no perforations, deaths, myocardial infarctions or need for bypass surgery. Our findings suggest that successful recanalization of chronic total occlusions can be achieved with a high success rate using the ChoICE PT wire. A strategy of progressively resecting the more floppy and kinked distal end can provide multiple uses from a single wire, optimizing recanalization success and obviating the need for additional wires.

Epileptic seizures attributed to cerebral hyperperfusion after percutaneous transluminal angioplasty and stenting of the internal carotid artery.

Cerebral hyperperfusion syndrome as a complication of carotid endarterectomy (CEA) has been widely reported in the surgical literature. It may occur within hours to 3 weeks after CEA and is characterized by symptoms ranging from headaches, fits, confusion, focal neurological signs to intracerebral hemorrhage. Although percutaneous transluminal angioplasty (PTA) and stenting are increasingly performed as an alternative to CEA in the treatment of carotid artery stenosis, few cases of cerebral hyperperfusion injury following carotid stenting have been reported. We describe 2 cases of cerebral hyperperfusion syndrome following PTA and stenting for high-grade internal carotid artery (ICA) stenosis. Both cases involved a lesion of 95% in severity. The first case was a 73-year-old man who developed generalized convulsion 7 h following stenting to the left ICA. The second case was an 80-year-old woman who developed recurrent right periorbital headache and confusion 16 h after stenting to the right ICA, followed by left upper limb seizure 14 days later. Both patients fully recovered without any intracerebral hemorrhage or infarction. To our knowledge, this is the first report of cerebral hyperperfusion injury after carotid stenting without associated intracranial hemorrhage and with full recovery. In the patient with neurological symptoms following carotid stenting, it is important to consider cerebral hyperperfusion syndrome as a differential diagnosis to embolic or hemorrhagic stroke since early recognition and meticulous control of blood pressure may prevent progression to cerebral hemorrhage and death.

Global experience in cervical carotid artery stent placement.

The purpose of this article is to review and update the current status of carotid artery stent placement in the world. Surveys to major interventional centers in Europe, North and South America, and Asia were initially completed in June 1997. Subsequent information from these 24 centers in addition to 12 new centers has been obtained to update the information. The survey asked the various questions regarding the patients enrolled, procedure techniques, and results of carotid stenting, including complications and restenosis. The total number of endovascular carotid stent procedures that have been performed worldwide to date included 5,210 procedures involving 4,757 patients. There was a technical success of 98.4% with 5,129 carotid arteries treated. Complications that occurred during the carotid stent placement or within a 30-day period following placement were recorded. Overall, there were 134 transient ischemic attacks (TIAs) for a rate of 2.82%. Based on the total patient population, there were 129 minor strokes with a rate of occurrence of 2.72%. The total number of major strokes was 71 for a rate of 1.49%. There were 41 deaths within a 30-day postprocedure period resulting in a mortality rate of 0.86%. The combined minor and major strokes and procedure-related death rate was 5.07%. Restenosis rates of carotid stenting have been 1.99% and 3.46% at 6 and 12 months, respectively. The rate of neurologic events after stent placement has been 1.42% at 6-12-month follow-up. Endovascular stent treatment of carotid artery atherosclerotic disease is growing as an alternative for vascular surgery, especially for patients that are high risk for standard carotid endarterectomy. The periprocedure risks for major and minor strokes and death are generally acceptable at this early stage of development and have not changed significantly since the first survey results. Cathet. Cardiovasc. Intervent. 50:160-167, 2000.

Preliminary neuropsychological outcomes of angioplasty and stenting of extracranial cerebral arteries.

Preliminary evaluation of the neuropsychological status of three Chinese-speaking patients receiving angioplasty and stenting of extracranial cerebral arteries showed no significant decline in their performance on cognitive tasks measuring (1) memory function, verbal and nonverbal memory, (2) attention, and (3) cognitive processing speed. Although angioplasty and stenting of extracranial cerebral arteries did not appear associated with detrimental changes in the cognitive status of the two patients completing all cognitive tasks, their relation must be confirmed as a neuropsychologically safe measure for reducing the risk of stroke in Chinese with significant extracranial cerebral artery stenosis by a randomized controlled study with a much larger sample.

Stenting of a renal artery bifurcation stenosis.

Renal artery stenosis involving the renal artery ostium often responds suboptimally to balloon angioplasty. In this context, immediate and long-term results can be optimized by stenting. Occasionally, lesions may involve the midartery segment at a branch point. We report a case of a bifurcation lesion which responded poorly to balloon angioplasty despite the kissing balloon technique. Excellent angiographic result was finally achieved by deploying two flexible coil stents in a "kissing" fashion. The patient's hypertension came under control overnight. At 6-month follow up, he remained normotensive on no medication. Repeat renal angiogram also showed no restenosis.

Prevalence of extracranial carotid and vertebral artery disease in Chinese patients with coronary artery disease.

BACKGROUND AND PURPOSE: Chinese have been reported to have an extremely low prevalence rate of carotid and vertebral artery disease in comparison with whites. Previous studies, however, have been limited to general hospital stroke admission or postmortem series and were prone to selection bias. Extracranial cerebrovascular disease (ECCVD) is associated with coronary artery disease (CAD) in whites. Data associating ECCVD with CAD in Chinese patients are not available. METHODS: We studied 153 consecutive Chinese patients with angiographically documented CAD. Duplex ultrasonography was performed to identify any underlying extracranial carotid and vertebral artery disease. Patient demographics; vascular risk factors; history of myocardial infarction, transient ischemic attack (TIA) or stroke; concomitant peripheral vascular disease (PVD); degree of left ventricular dysfunction; and extent and severity of CAD were also noted and analyzed. RESULTS: Significant (> or = 50%) stenosis of one or more of the extracranial cerebral arteries was found in 32 patients (21%). The internal and external carotid arteries were involved in 17 of 153 patients (11%) and 19 of 153 patients (12%), respectively. The vertebral artery was involved in 9 of 153 patients (6%) and the common carotid artery in 3 of 153 (2%). Diabetes mellitus, hypertension, a history of TIA or stroke, and PVD were significantly associated with the presence of ECCVD. CONCLUSIONS: Significant ECCVD is not uncommon in Chinese patients with CAD, and the prevalence is comparable with that reported in white populations. Patients with a history of diabetes, hypertension, TIA, stroke, and PVD are more likely to have concomitant ECCVD.

Hemodynamic effects and clinical determinants of defibrillation threshold for transvenous atrial defibrillation using biatrial biphasic shocks in patients with chronic atrial fibrillation.

We assessed the relationship between the hemodynamic changes and shock intensity in transvenous atrial defibrillation for chronic AF. The correlation between the clinical profile and atrial DFT and the factors predicting maintenance of SR after successful defibrillation were also investigated. Atrial defibrillation using entirely transvenous leads has been investigated as an alternative means of managing patients with AF. However, the hemodynamic consequence of this technique and the clinical factors predicting defibrillation efficacy have not been evaluated. Thirty-seven patients with chronic AF (4 weeks to 60 months) underwent transvenous atrial defibrillation. Defibrillation was performed by delivering R wave synchronized, biphasic (3/3 ms) shocks with step-up voltages (20-400 V) between defibrillation catheters in the anterolateral right atrium and the distal coronary sinus. Clinical profile of the patients, the DFT, arterial blood pressure, and RR interval during defibrillation and the 6-month recurrence rate were determined. SR was restored in 33 (89%) of 37 patients and the DFT was 3.7 +/- 1.4 J (317 +/- 58 V). Transvenous atrial defibrillation resulted in a mild reduction in blood pressure (6 +/- 10 mmHg), but substantial prolongation of longest postshock RR intervals (507 +/- 546 ms), which were significantly related to the shock intensity (r = 0.5, P < 0.001). There was no ventricular proarrhythmia. The patients' age, body weight, duration of AF, left atrial diameter, and ejection fraction were not related to the success of defibrillation, not the 6-month maintenance rate of SR (39%). However, the patients' age was related to DFT. Apart from transient reduction in blood pressure and shock related pauses that may require backup pacing, transvenous biatrial defibrillation was a highly effective and well-tolerated technique. The absence of clinical determinant for successful defibrillation suggests that restoring SR by transvenous atrial defibrillation could be attempted in most patients with chronic AF.

Initial clinical experience with an implantable human atrial defibrillator.

Low energy biatrial shock is an effective means of restoring sinus rhythm in patients with atrial fibrillation (AF). Ventricular proarrhythmia is avoided provided that shocks are well synchronized to R waves that are not at closely coupled intervals or preceded by long-short cycles. Based on these principles, an implantable atrial defibrillator has been developed and was implanted in three patients with drug refractory paroxysmal AF. The device detects AF via an actively fixed right atrial and a self-retaining coronary sinus defibrillating leads, and delivers 3/3 ms biphasic shocks up to 300 V synchronized to the R wave. The mean implant threshold (ED50) was 195 V (1.8 J). and minimum voltage at conversion during follow-up assessments at 1, 3, and 6 months were 260 V, 2.5 J. 250 V, 2.3 J, and 300 V, 3.0 J respectively. Detection of AF was 100% specific and shocks were 100% synchronized, although only a proportion of synchronized R waves were considered suitable for shock delivery primarily because of closely coupled cycles. Three patients had 9 spontaneous AF episodes, 8/9 (89%) successfully defibrillated by shocks of 260-300 V. Sedation was not used in 4 out of 9 (45%) episodes. Backup ventricular pacing was initiated by the device in 6 out of (67%) episodes. One patient had more frequent AF after lead placement, which subsided after a change of medication. There was no ventricular proarrhythmia. It is concluded that an implantable atrial defibrillator is a viable therapy for selected patients with paroxysmal AF. The device is capable of accurate AF detection, R wave synchronization and ventricular support pacing after successful defibrillation of AF.

Interference of cellular phones with implanted permanent pacemakers.

BACKGROUND AND HYPOTHESIS: Occasional reports have suggested that cellular phones may interfere with permanent pacemakers. Our investigation sought to determine systematically the effects of commercially available cellular phones on the performances of different pacing modes and sensing lead configurations of permanent implanted pacemakers. METHODS: We conducted the study in 29 patients implanted with single- or dual-chamber bipolar rate-adaptive permanent pacemakers (a total of nine different models and six different sensors: minute ventilation, activity sensing using either accelerometer or piezoelectric crystal, QT and oxygen saturation sensing) from four different manufacturers. Three different cellular phones with analog or digital coding with maximum power from 0.6 to 2 W were used to assess the effect of pacemaker interference. Each cellular phone was positioned at (1) above the pacemaker pocket, (2) the ear level ipsilateral to the pacemaker pocket, and (3) the contralateral ear level. Surface electrocardiograms, intracardiac electrograms, and marker channels were recorded where possible during the following maneuvers at each position: (1) calls made by a stationary phone to cellular phone, and (2) calls made from the cellular phone to a stationary phone. A total of eight different pacing modes [DDD(R), VDD(R), AAI(R) and VVI(R)] in both unipolar and bipolar sensing configurations was tested. RESULTS: Interference was demonstrated during cellular phone operation in 74 of 2,418 (3.1%) episodes in eight patients. Three types of interference were observed: inhibition of pacing output, rapid ventricular tracking in DDD(R) or VDD(R) mode, and asynchronous pacing. All were observed only with the cellular phone positioned above the pacemaker pocket. Interference occurred prior to and after the termination of the ringing tone of the cellular phone in 57% of cases. Cellular phones with either digital or analog technology could cause interference. Unipolar atrial lead was most susceptible to interference (relative frequency of interference: unipolar 1.8%, bipolar 0.4%, p < 0.05; atrial 2.9%, ventricular 1%, p < 0.05). There was no sensor-driven rate acceleration during all tests. In all patients, reprogramming of the sensitivity level successfully prevented cellular phone interference. CONCLUSIONS: Commercially available cellular phones can cause reversible interference to implanted single- or dual-chamber permanent pacemakers. The effect is maximal with high atrial unipolar sensitivity, especially in single pass VDD(R) systems. Both digital and analog cellular phones can lead to interference. Pacemaker interference can occur prior to a warning sign (ringing tone) of the phone and may have significant implications in patient safety.

Behavior of late potentials on the body surface during programmed ventricular stimulation.

OBJECTIVES: This study sought to evaluate the behavior of late potentials on the body surface by signal averaging during programmed stimulation and to correlate the findings with the cycle length of induced ventricular tachycardia. BACKGROUND: Clinically relevant late potentials may be concealed within the QRS complex and may be missed by the conventional signal-averaged electrocardiogram (SAECG). In contrast, some late potentials may arise from dead-end pathways or pathways not capable of supporting sustained ventricular tachycardia (VT). It has been shown that durations of late potentials in sinus rhythm correlate poorly with VT cycle length. METHODS: Signal-averaged electrocardiography during sinus rhythm, right ventricular pacing (S1) and introduction of a right ventricular extrastimulus (S2) was performed in 95 patients: 11 patients with a structurally normal heart and no inducible VT (Group I); 44 with a previous myocardial infarction (MI) and no inducible monomorphic VT (Group II); and 40 with a previous MI and inducible monomorphic VT (Group III). RESULTS: The best subset of SAECG variables and the best cut points for each variable to differentiate between patients with and without VT were first established for each rhythm studied. Total duration of the filtered QRS complex (QRSD) was found to be the only independent predictor of inducibility of VT. When late potentials were defined for these criteria (QRSD > OR = 113, > or = 178 and > or = 168 ms for the SAECG during sinus rhythm, S1 and S2, respectively), there was no difference in the incidence of false positive (16% vs. 18%) or false negative (30% vs. 26%) late potentials between sinus rhythm and S1. During S2, there were significantly fewer false positive late potentials (11% vs. 16%) and fewer false negative late potentials (17% vs. 30%) than with sinus rhythm. Compared with sinus rhythm, 31% of the false positive late potentials detected during sinus rhythm were lost, whereas 43% of the false negative late potentials became detectable after S2, resulting in improved sensitivity (83% vs. 70%), specificity (89% vs. 84%) and predictive accuracy (86% vs. 77%, p < 0.05). Among the patients with VT, QRSD during S2 achieved the best correlation with VT cycle length (r = 0.74) and was the only independent predictor of VT cycle length when all SAECG variables were considered. CONCLUSIONS: Late potentials revealed by ventricular extrastimuli but concealed during sinus rhythm may be clinically relevant and may explain some of the false negative late potentials and reduced sensitivity of the conventional SAECG in predicting VT. In contrast, those late potentials that are detected during sinus rhythm but lost after ventricular extrastimuli are often clinically irrelevant and may account for the false positive late potentials and reduced specificity of the conventional SAECG.

Ureteropelvic junction obstruction in upper and lower moiety of duplex renal systems.

OBJECTIVES: To review our experience with ureteropelvic junction obstruction in a duplicated renal collecting system. METHODS: The records of 7 patients with ureteropelvic junction obstruction in a duplex collecting system were reviewed. In addition to routine demographics, each case was reviewed for presenting symptoms, site of obstruction, and type of surgical treatment. RESULTS: Three of the 7 cases involved obstruction of the upper pole moiety, and the remaining 4 involved the lower pole segment of a duplex system. Obstruction of the upper and lower pole segments was found in both incomplete and complete duplicated collecting systems. CONCLUSIONS: Careful preoperative evaluation of patients with ureteropelvic junction obstruction will usually identify segmental obstruction in a duplicated system. Treatment should be individualized based on site of obstruction and degree of function remaining in the affected segment.

Rapid intravenous infusion of d-1 sotalol: time to onset of effects on ventricular refractoriness, and safety.

d-1 sotalol is one of the most effective antiarrhythmic agents currently available for ventricular tachyarrhythmias, but the recommended infusion rate of 10-20 min is too slow for rapid pharmacological termination of sustained ventricular tachycardia (VT) or for use during cardiac arrest. The safety of the drug and time lag from its rapid administration to onset of significant effects on ventricular refractoriness is unknown. One hundred and nine patients with a history of spontaneous and inducible sustained ventricular tachyarrhythmias were studied. d-1 sotalol (1.5 mg.kg-1) was infused over 5 min in the first 57 patients (mean age 61 +/- 13 years, mean ejection fraction 37 +/- 15%, range 15-70%). d-1 sotalol was then given over 1 min in the next 52 patients (mean age 61 +/- 12 years, mean ejection fraction 35 +/- 11%, range 18-58%). The time course of change in right ventricular effective refractory period (RVERP) was measured in 15 consecutive patients following the 5 min infusion and in all 52 patients following the bolus injection. Following the 5 min infusion, RVERP increased rapidly from a baseline of 231 +/- 17 ms, reaching a plateau of 268 +/- 23 ms at 10 min. Following the 1 min injection, RVERP increased virtually immediately from a baseline of 237 +/- 25 ms to reach a plateau of 271 +/- 31 ms at 5 min. Two patients (one in each group) developed symptomatic hypotension; both responded to volume replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Sizing the Gianturco-Roubin coronary flexible coil stent.

The balloon expandable, stainless steel, flexible coil stent is a useful device for the management of acute or threatened closure after percutaneous transluminal coronary angioplasty. Appropriate sizing is important to optimize immediate results and reduce the risk of acute thrombosis and restenosis. The in vivo size at deployment of this stent at nominal inflation pressures has not been evaluated. Forty patients who received a single flexible coil stent (10 patients each for stent sizes 4.0, 3.5, 3.0, and 2.5 mm) were studied. The stents were deployed at 3-5 atmospheres. The actual stent size achieved by the stent during deployment was found to be significantly less than the nominal size, being 3.7 +/- 0.3, 3.2 +/- 0.2, and 2.8 +/- 0.2 mm for nominal stent sizes of 4.0, 3.5, and 3.0 mm, respectively (P < 0.005, P < 0.001, and P < 0.01). For a 2.5 mm stent, it was 2.4 +/- 0.2 mm (P = ns). Thus, for optimal results with this device, we recommend that vessels 2.0-2.4 mm in diameter be supported by a 2.5 mm stent, vessels 2.5-2.9 mm in diameter by a 3.0 mm stent, vessels 3.0-3.4 mm in diameter by a 3.5 mm stent, and vessels 3.5-4.0 mm in diameter by a 4.0 mm stent.