Coronary artery perforation during percutaneous intervention: incidence and outcome.

OBJECTIVE: To examine the clinical outcome of percutaneous coronary intervention where the procedure was complicated by vessel perforation. SETTING: Tertiary referral centre. METHODS: The procedural records of 6245 patients undergoing coronary intervention were reviewed. In 52 patients (0.8%) the procedure was complicated by vessel perforation, ranging from wire exit to free flow of contrast into the pericardial space. The majority of lesions treated were complex (37% type B, 59% type C) and 9 of 52 (17%) were chronic occlusions. Ten patients (19%) received abciximab. Four underwent rotational atherectomy (8%). RESULTS: In 28 of 52 patients (54%) the perforation was benign and managed conservatively without the development of haemodynamically significant sequelae. In 24 of 52 (46%) a significant pericardial effusion ensued requiring drainage. Of these 24 procedures 6 had involved the treatment of a chronic occlusion (25%). Eight of the 24 patients were referred for emergency bypass surgery (33%), 3 of whom died. Of the remaining 16 not referred for surgery, 3 died. Of the 10 procedures complicated by vessel perforation where abciximab had been administered, 9 (90%) led to pericardial tamponade. Latterly 2 vessel perforations were successfully treated by the deployment of a covered stent. CONCLUSIONS: Coronary artery perforation with sequelae during intervention is rare--26 of 6245 (0.4%). This complication was seen in the treatment of chronic occlusions, which are therefore not risk-free procedures. The development of pericardial tamponade carries a high mortality. While prompt surgical intervention may be life saving, expertise in the use of covered stents may provide a valuable rescue option for this serious complication. Caution should be exercised where coronary perforation occurs and abciximab has been used.

The size and albedo of the Kuiper-belt object (20000) Varuna.

Observations over the last decade have revealed the existence of a large number of bodies orbiting the Sun beyond Neptune. Known as the Kuiper-belt objects (KBOs), they are believed to be formed in the outer reaches of the protoplanetary disk around the young Sun, and have been little altered since then. They are probably the source of short-period comets. The KBOs are, however, difficult objects to study because of their distance from earth, so even basic physical properties such as their sizes and albedos remain unknown. Previous size estimates came from assuming an albedo with the canonical value being 0.04. Here we report simultaneous measurements of the thermal emission and reflected optical light of the bright KBO (20000) Varuna, which allow us to determine independently both the size and the albedo. Varuna has an equivalent circular diameter of D = 900+129-145 km and a red geometric albedo of pR = 0.070+0.030-0.017. Its surface is darker than Pluto's, suggesting that it is largely devoid of fresh ice, but brighter than previously assumed for KBOs.

Development and validation of a Bayesian index for predicting major adverse cardiac events with percutaneous transluminal coronary angioplasty.

OBJECTIVE: To create a risk model for predicting major adverse complicating events of percutaneous transluminal coronary angioplasty (PTCA), and to test the accuracy of the model on a prospective cohort of patients SETTING: Tertiary cardiac centre METHODS: Available software can predict probabilities of events using Bayes's theorem. To establish the accuracy of these predictive tools, a Bayes table was created to evaluate major adverse complicating events (MACE)-death, emergency coronary artery bypass grafting (CABG), or Q wave infarct occurring during the in-patient episode-on the first 1500 patients in the department PTCA database (development group); the predictive value of this model was then tested with the subsequent 1000 patients (evaluation group). The following probabilities were assessed to determine their association with MACE: age, sex, left ventricular function, American Heart Association lesion morphology classification, cardiogenic shock, previous CABG, diabetes, hypertension, multivessel PTCA. MAIN OUTCOME MEASURES: To establish the discriminatory ability of the predictive index, calibration plots and receiver operating characteristic (ROC) curves were obtained to compare the development and evaluation groups. RESULTS: The ROC curve plotted to determine the discriminatory value of the Bayesian table created from the development group (n = 1500) in predicting MACE in the evaluation group (n = 1000) showed a moderately predictive area under the curve of 0.76 (SEM 0.07). This predictive accuracy was confirmed with separately constructed calibration plots. CONCLUSIONS: Accurate predictions of MACE can be identified in populations undergoing percutaneous intervention. The database used allows operators to obtain consent from patients appropriately from their own experience rather than from other published data. If a national PTCA database existed along similar lines, individual operators and interventional centres could compare themselves with nationally available data.

Angiographic and clinical restenosis following the use of long coronary Wallstents.

This study assessed clinical and angiographic restenosis following the deployment of the long coronary Wallstent. Between May 1995 and June 1997, 182 Wallstents were deployed in 162 vessels in this unit. Forty-eight percent had an unstable coronary syndrome and 94% had AHA grade B or C lesions. The mean lesion length was 37 +/- 20 mm and the mean stent length was 48 +/- 20 mm. The procedural success rate was 99% and the primary success rate was 93%. Six in-patients suffered subacute stent thrombosis, the majority being in the era of anticoagulation rather than antiplatelet regimes. Seventy-three percent remained free of major adverse clinical events in the follow-up period, but 41% had angiographic restenosis. The Wallstent can be deployed in complex lesions with a high primary success rate and an acceptably low restenosis rate. The optimal management of in-stent restenosis remains to be defined.

Evaluation of myocardial, hepatic, and renal perfusion in a variety of clinical conditions using an intravenous ultrasound contrast agent (Optison) and second harmonic imaging.

OBJECTIVE: To assess the potential of intravenous Optison, a second generation ultrasound contrast agent, and various ultrasound imaging modes to determine myocardial, kidney, and liver perfusion in normal subjects and patients with left ventricular dysfunction or chronic pulmonary disease together with renal or hepatic dysfunction. METHODS: Five normal subjects and 20 patients underwent grey scale echocardiographic imaging of myocardium, kidney, and liver during 505 intravenous injections of Optison. Images were assessed qualitatively by two independent observers and quantitatively using video densitometry to determine the peak contrast enhancement effect. RESULTS: Qualitative analysis showed that intermittent harmonic imaging was superior to either conventional fundamental or continuous harmonic imaging for all organs. Quantitative analysis showed that the peak change in echocardiographic intensity v baseline during continuous harmonic imaging was 11 units for myocardium (p < 0.03), 7 units for kidney (NS), and 14 units for liver (p < 0.05). During intermittent harmonic imaging the peak change was significantly greater, being 33 units for myocardium (p < 0.0001), 24 units for kidney (p < 0.0002), and 16 units for liver (p < 0.001). CONCLUSIONS: Organ tissue perfusion can be demonstrated following intravenous injection of Optison, particularly when used in combination with intermittent harmonic imaging techniques. This contrast agent is effective in a variety of clinical conditions.

Chemistry in cometary comae.

Significant gas-phase chemistry occurs in the comae of bright comets, as is demonstrated here for the case of Comet Hale-Bopp. The abundance ratio of the two isomers, hydrogen cyanide and hydrogen isocyanide, is shown to vary with heliocentric distance in a way that is consistent with production of HNC by ion-molecule chemistry initiated by the photoionization of water. Likewise, the first maps of emission from HCO+ show an abundance and an extended distribution that are consistent with the same chemical model.

Chemical processing in the coma as the source of cometary HNC.

The discovery of hydrogen isocyanide (HNC) in comet Hyakutake with an abundance (relative to hydrogen cyanide, HCN) similar to that seen in dense interstellar clouds raised the possibility that these molecules might be surviving interstellar material. The preservation of material from the Sun's parent molecular cloud would provide important constraints on the processes that took place in the protostellar nebula. But another possibility is that HNC is produced by photochemical processes in the coma, which means that its abundance could not be used as a direct constraint on conditions in the early Solar System. Here we show that the HNC/HCN ratio determined for comet Hale-Bopp varied with heliocentric distance in a way that matches the predictions of models of gas-phase chemical production of HNC in the coma, but cannot be explained if the HNC molecules were coming from the comet's nucleus. We conclude that HNC forms mainly by chemical reactions in the coma, and that such reactions need to be considered when attempting to deduce the composition of the nucleus from observations of the coma.

Deuterium in comet C/1995 O1 (Hale-Bopp): detection of DCN.

Deuterated hydrogen cyanide (DCN) was detected in a comet, C/1995 O1 (Hale-Bopp), with the use of the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. The inferred deuterium/hydrogen (D/H) ratio in hydrogen cyanide (HCN) is (D/H)HCN = (2.3 +/- 0.4) x 10(-3). This ratio is higher than the D/H ratio found in cometary water and supports the interstellar origin of cometary ices. The observed values of D/H in water and HCN imply a kinetic temperature >/=30 +/- 10 K in the fragment of interstellar cloud that formed the solar system.

Randomised trial of elective stenting after successful percutaneous transluminal coronary angioplasty of occluded coronary arteries.

BACKGROUND: The value of angioplasty in occluded coronary arteries is limited by a restenosis/reocclusion rate of 50-70%. In patients with subtotal occlusion, stent implantation has been shown to reduce clinical and angiographic restenosis. Retrospective observational studies have suggested that stenting could reduce restenosis in total occlusions. The value of sustained coronary patency on global and regional left ventricular function in this clinical setting has not been defined clearly. OBJECTIVES: To assess the medium term effect of elective intracoronary stent deployment after successful percutaneous transluminal coronary angioplasty (PTCA) of an occluded coronary artery. METHODS: Sixty patients with a total coronary occlusion successfully treated by PTCA were randomised to receive an intracoronary stent or no stent. Patients underwent clinical and angiographic follow up at six months. RESULTS: Thirty patients received a stent (group A) and 30 were treated by angioplasty alone (group B), all with initial success. One patient in group B required repeat angioplasty with stenting at 24 hours and one patient died after 10 days. Angiographic follow up was available for 57 patients. This showed a significantly reduced reocclusion rate in group A compared with group B (7% v 29%, p < 0.01) and a tendency to a reduced restenosis rate (22% v 40%, p = 0.105) in patients with no reocclusion. Left ventricular function, both global and regional, improved in group A. Only the regional left ventricular function in the area supplied by the target coronary artery improved in group B. Recurrence of symptoms and clinical events such as repeat angioplasty, coronary artery bypass grafting, death or myocardial infarction tended to be reduced in group A (4 (13%) v 9 (30%)). CONCLUSIONS: Intracoronary stent insertion is effective in reducing the rate of reocclusion and shows a trend towards reduced restenosis after opening of a total coronary occlusion by balloon angioplasty. Sustained patency of the target coronary artery is associated with improvement in global and regional left ventricular function.

A determination of the HDO/H2O ratio in comet C/1995 O1 (Hale-Bopp).

Deuterated water (HDO) was detected in comet C/1995 O1 (Hale-Bopp) with the use of the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. The inferred D/H ratio in Hale-Bopp's water is (3.3 +/- 0.8) x 10(-4). This result is consistent with in situ measurements of comet P/Halley and the value found in C/1996 B2 (Hyakutake). This D/H ratio, higher than that in terrestrial water and more than 10 times the value for protosolar H2, implies that comets cannot be the only source for the oceans on Earth.

Measurements of 12C/13C, 14N/15N, and 32S/34S ratios in comet Hale-Bopp (C/1995 O1).

The 12C/13C, 14N/15N, and 32S/34S isotope ratios in comet Hale-Bopp (C/1995 O1) were determined through observations taken with the James Clerk Maxwell Telescope. Measurements of rare isotopes in HCN and CS revealed isotope ratios of H12CN/H13CN = 111 +/- 12, HC14N/HC15N = 323 +/- 46, and C32S/C34S = 27 +/- 3. Within the measurement uncertainties, the isotopic ratios are consistent with solar system values. The cometary volatiles thus have an origin in the solar system and show no evidence for an interstellar component.

Decrease in factor VII coagulant activity during percutaneous transluminal coronary angioplasty by heparin-mediated lipolytic action.

Levels of factor VII coagulant activity (FVII:C) and two-chain factor VIIa antigen (FVIIa:Ag) were measured in ten patients before and up to 6 h after receiving a bolus of heparin during percutaneous transluminal coronary angioplasty (PTCA). A significant and sustained post-heparin fall in the level of FVII:C was observed (approximately 30%) without any change in the level of FVIIa:Ag. The level of tissue factor antigen within the circulation remained unchanged. The observed decrease in FVII:C coincided with a significant decrease in triglyceride levels presumably due to lipoprotein and hepatic lipase released by the heparin. These findings appear to demonstrate a lipid (triglyceride) dependence of FVII:C. Thus, heparin may act indirectly as antithrombotic agent by limiting a lipid-dependent activation of the extrinsic pathway of coagulation.

The HNC/HCN ratio in comets.

The abundance ratio of the isomers HCN and HNC has been investigated in comet Hale-Bopp (C/1995 O1) through observations of the J = 4-3 rotational transitions of both species for heliocentric distances 0.93 < r < 3 AU, both pre- and post-perihelion. After correcting for the optical depth of the stronger HCN line, we find that the column density ratio of HNC/HCN in our telescope beam increases significantly as the comet approaches the Sun. We compare this behavior to that predicted from an ion-molecule chemical model and conclude that the HNC is produced in significant measure by chemical processes in the coma; i.e., for comet Hale-Bopp, HNC is not a parent molecule sublimating from the nucleus.

The potential thrombogenic action of a nonionic radiographic contrast medium used during coronary angiography is offset by heparin during coronary angioplasty.

Iohexol sodium, a nonionic radiographic contrast medium, used in invasive imaging techniques has been shown to be potentially thrombogenic. In the present study, the effect of iohexol sodium on haemostatic factors was evaluated in 20 patients, 16 male and 4 female, 10 undergoing coronary angiography and another 10 undergoing coronary angioplasty. All the patients had angiographically-assessed coronary artery disease. The patients undergoing coronary angioplasty received a significantly larger quantity of the dye as compared with the patients undergoing coronary angiography. The former group of patients also received a bolus of 20,000 units of standard heparin in addition. The levels of thrombin-antithrombin-III complex (TAT), prothrombin fragments 1 and 2 (F1F2), D-dimer and the functional activity of tissue factor pathway inhibitor (TFPI) were assayed. While the baseline and 30-min post-dye levels of TAT and F1F2 were comparable in patients undergoing coronary angioplasty, the 30 min levels were significantly elevated in patients undergoing coronary angiography. The post-dye levels of TFPI activity were significantly increased in the former group due to the heparin-induced release of TFPI. It is concluded that the thrombogenic potential of iohexol sodium was overcome by heparin used routinely during coronary angioplasty.

Association of antibodies to heat-shock protein-65 with percutaneous transluminal coronary angioplasty and subsequent restenosis.

Heat-shock protein (HSP)-65 of mycobacterial origin has been implicated in the mediation of atherosclerosis by immune mechanisms. Any role of HSP-65 in mediating restenosis is however not clear. We determined the anti-HSP-65 antibodies in 28 patients, 25 male and 3 female, aged 35 to 78 years, with coronary artery disease (CAD) and undergoing percutaneous transluminal coronary angioplasty (PTCA). Of the 28 patients, 12 suffered restenosis five to seven months later. The serum levels of antibody were measured at baseline, immediately after PTCA, before discharge from the hospital, and at 6 weeks, 3 and 6 months after the performance of PTCA. The antibody levels were expressed in OD U/log titre, as explained in the text, and termed estimated OD or EOD. The control group consisted of 29 healthy volunteers, 16 male and 13 female, aged 24 to 59 years. The mean EOD of the patients at baseline was higher than that of the controls (0.60 +/- 0.12, SD; 95% CI 0.56-0.64 compared with 0.53 +/- 0.13; 0.48-0.58; p < 0.01). There were no correlation between age and EOD of patients, controls or both taken together, ruling out the influence of age on the EOD changes in the given age range. The mean antibody levels of the patients with CAD were similar whether or not they suffered subsequent restenosis (0.61 +/- 0.15; 0.53-0.69 in the patency group, and 0.60 +/- 0.10; 0.54-.066 in the restenosis group). However, the patients who did not develop restenosis had a drop in their antibody levels immediately after PTCA (0.51 +/- 0.14; 0.48-0.55; 2-tailed p = 0.029), and at discharge from the hospital (0.52 +/- 0.15; 0.44-0.60; p = 0.036) as compared with the baseline. This decrease of antibodies was not observed in the restenosis group. Furthermore, the anti-HSP-65 antibody levels remained slightly low throughout the 6-month follow-up in the patients with patent coronaries as compared with patients who restenosed, but the decrease was statistically not significant at 5% level at any stage. Besides the anti-HSP-65 antibodies, the levels of anticardiolipin (ACL) antibody were also measured in all the patients. The levels of the ACL antibody were found to be within the normal range before and at all stages after PTCA, ruling out the PTCA-associated change in the anti-HSP-65 antibody as a non-specific occurrence. Thus, a drop in the level of antibody against HSP-65 after PTCA seemed to be associated with a favourable outcome, and may serve as a useful prognostic marker of coronary angioplasty.

Observations of carbon monoxide in comet Hale-Bopp.

The recently discovered comet Hale-Bopp (C/1995 01) sports a bright dust coma even though it is still far from the sun (presently 6 astronomical units). This feature has attracted considerable interest in the public and scientific arenas. The comet is headed toward perihelion at 0.92 astronomical unit in April 1997 and is widely expected to then become a spectacular naked-eye comet. With millimeter-wave observations, carbon monoxide (CO) has been identified as the driver for the early activity observed in Hale-Bopp.

Spontaneous haemothorax as a complication of anti-coagulation following coronary angioplasty.

Haemorrhagic complications are well recognized when heparin is used during percutaneous transluminal coronary angioplasty (PTCA). We present a 74-year-old female who developed a large acute spontaneous haemothorax 20 h after coronary angioplasty. Spontaneous haemothorax has rarely been described and is predominantly associated with pulmonary embolism. In the absence of a pulmonary embolus, a spontaneous haemothorax during anti-coagulation has only been described twice in the world literature since 1862 (1). This is the first description of this complication following the use of heparin during PTCA.

Echocardiographic assessment of systolic and diastolic left ventricular function using an automatic boundary detection system. Correlation with established invasive and non invasive parameters.

Systolic and diastolic left ventricular function was assessed using an echocardiographic automatic boundary detection system (ABD) in 50 unselected patients undergoing left cardiac catheterisation. Automatic boundary detection system derived parameters (fractional area change [FAC], peak positive rate of area change [+dA/dt] and peak negative rate of area change [-dA/dt]) were compared with invasively (left ventricular angiography and pressures) and non invasively (Doppler mitral filling velocities and isovolumic relaxation time) acquired conventional indices of ventricular function. Adequate detection of endocardial boundaries and subsequent measurements using the ABD system were achieved in 40/50 (80%) patients in the short axis parasternal view, in 41/50 (82%) in the apical four chamber view and in 34/50 (68%) in both views. For the whole group of patients the FAC (maximal left ventricular diastolic area--minimal left ventricular systolic area/maximal left ventricular diastolic area) estimated in the short axis view correlated with the angiographic ejection fraction (EF) measured in the right oblique projection (r = 0.51, p < 0.001). There was only a weak correlation of the FAC estimated in the apical four chamber view with the EF (r = 0.36, p < 0.01). The mean FAC (mean value of the FAC in the short axis and apical four chamber views) correlated reasonably with the EF (r = 0.62, p < 0.0001). There was no correlation between ABD derived parameters and left ventricular end diastolic pressure (LVEDP) in these patients. In a subgroup of patients with normal coronary arteries and left ventricular function (n = 17), although there was no correlation between EF and FAC, there was a strong positive correlation between FAC (apical four chamber and mean) and LVEDP (r = 0.77, p < 0.01 and r = 0.87, p < 0.01 respectively). No correlation was found in these patients between EF and LVEDP. In a further subgroup of patients with angiographically abnormal left ventricular function (EF < 45%), there was a positive correlation between FAC (short axis, apical four chamber and mean) and EF (r = 0.52, p < 0.05, r = 0.83, p < 0.0001 and r = 0.80, p < 0.001 respectively) and a negative correlation between FAC (short axis and mean) and LVEDP (r = -0.52, p < 0.05 and r = -0.60, p < 0.01 respectively). There was also a negative correlation between LVEDP and EF in the same subgroup of patients (r = -0.65, p < 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of clinical outcome after elective and "bail out" coronary stent insertion.

BACKGROUND: Coronary stents may be used electively during percutaneous transluminal coronary angioplasty (PTCA) or as a "bail-out" device to treat abrupt or threatened vessel closure following PTCA. OBJECTIVE: To compare the clinical outcome of elective and "bail-out" coronary stent insertion. DESIGN: A retrospective analysis of all patients receiving coronary stents. SETTING: Tertiary referral center performing over 400 PTCA procedures a year. PATIENTS: Fifty-six patients (42 male), mean age 57 (range = 32 to 78) years received 67 Palmaz-Schatz coronary stents. Forty-nine stents were deployed as "bail-out" in 41 patients (abrupt vessel closure in 15 and threatened vessel closure in 26) and 18 stents were deployed electively in 15 patients. MAIN OUTCOME MEASURES: Myocardial infarction, repeat angiography, coronary artery bypass graft surgery and death. RESULTS: Stents were successfully deployed in 56/62 (90.3%) patients. In-hospital events were significantly more common in the "bail-out" group compared to the elective group. The in-hospital events, comparing the "bail-out" group versus the elective group, were as follows: Death 2/41 (4.9%) vs 0/15 (0%), coronary artery bypass graft surgery (CABG) 8/41 (19.5%) vs 0/15 (0%), stent thrombosis 3/41 (7.3%) vs 0/15 (0%), and myocardial infarction 6/41 (14.6%) vs 1/15 (6.7%) respectively. After discharge no patient died or had CABG. One patient in the "bail-out" group had a myocardial infarct (late stent thrombosis). Two patients from each group had repeat angiography because of recurrent angina in the 6 month follow up period. CONCLUSION: "Bail-out" stenting has an increased incidence of in-hospital complications compared to elective procedures. If these short-term problems can be overcome however, the clinical events in the first 6 months after leaving hospital are low and similar to patients under-going elective procedures.