Empirical landscape genetic comparison of single nucleotide polymorphisms and microsatellites in three arid-zone mammals with high dispersal capacity

Landscape genetics is increasingly transitioning away from microsatellites, with single nucleotide polymorphisms (SNPs) providing increased resolution for detecting patterns of spatial-genetic structure. This is particularly pertinent for research in arid-zone mammals due to challenges associated with unique life history traits, such as boom-bust population dynamics and long-distance dispersal capacities. Here, we provide a case study comparing SNPs versus microsatellites for testing three explicit landscape genetic hypotheses (isolation-by-distance, isolation-by-barrier, and isolation-by-resistance) in a suite of small, arid-zone mammals in the Pilbara region of Western Australia. Using clustering algorithms, Mantel tests, and linear mixed effects models, we compare functional connectivity between genetic marker types and across species, including one marsupial, Ningaui timealeyi, and two native rodents, Pseudomys chapmani and P. hermannsburgensis. SNPs resolved subtle genetic structuring not detected by microsatellites, particularly for N. timealeyi where two genetic clusters were identified. Furthermore, stronger signatures of isolation-by-distance and isolation-by-resistance were detected when using SNPs, and model selection based on SNPs tended to identify more complex resistance surfaces (i.e., composite surfaces of multiple environmental layers) in the best-performing models. While we found limited evidence for physical barriers to dispersal across the Pilbara for all species, we found that topography, substrate, and soil moisture were the main environmental drivers shaping functional connectivity. Our study demonstrates that new analytical and genetic tools can provide novel ecological insights into arid landscapes, with potential application to conservation management through identifying dispersal corridors to mediate the impacts of ongoing habitat fragmentation in the region.

Linking life history to landscape for threatened species conservation in a multiuse region

Landscape-scale conservation that considers metapopulation dynamics will be essential for preventing declines of species facing multiple threats to their survival. Toward this end, we developed a novel approach that combines occurrence records, spatial-environmental data, and genetic information to model habitat, connectivity, and patterns of genetic structure and link spatial attributes to underlying ecological mechanisms. Using the threatened northern quoll (Dasyurus hallucatus) as a case study, we applied this approach to address the need for conservation decision-making tools that promote resilient metapopulations of this threatened species in the Pilbara, Western Australia, a multiuse landscape that is a hotspot for biodiversity and mining. Habitat and connectivity were predicted by different landscape characteristics. Whereas habitat suitability was overwhelmingly driven by terrain ruggedness, dispersal was facilitated by proximity to watercourses. Although there is limited evidence for major physical barriers in the Pilbara, areas with high silt and clay content (i.e., alluvial and hardpan plains) showed high resistance to dispersal. Climate subtlety shaped distributions and patterns of genetic turnover, suggesting the potential for local adaptation. By understanding these spatial-environmental associations and linking them to life-history and metapopulation dynamics, we highlight opportunities to provide targeted species management. To support this, we have created habitat, connectivity, and genetic uniqueness maps for conservation decision-making in the region. These tools have the potential to provide a more holistic approach to conservation in multiuse landscapes globally.

Global Commitments to Conserving and Monitoring Genetic Diversity Are Now Necessary and Feasible

Global conservation policy and action have largely neglected protecting and monitoring genetic diversity—one of the three main pillars of biodiversity. Genetic diversity (diversity within species) underlies species’ adaptation and survival, ecosystem resilience, and societal innovation. The low priority given to genetic diversity has largely been due to knowledge gaps in key areas, including the importance of genetic diversity and the trends in genetic diversity change; the perceived high expense and low availability and the scattered nature of genetic data; and complicated concepts and information that are inaccessible to policymakers. However, numerous recent advances in knowledge, technology, databases, practice, and capacity have now set the stage for better integration of genetic diversity in policy instruments and conservation efforts. We review these developments and explore how they can support improved consideration of genetic diversity in global conservation policy commitments and enable countries to monitor, report on, and take action to maintain or restore genetic diversity.

Is the optimal blanking period duration after cryoballoon pulmonary vein isolation impacted by use of antiarrhythmic drugs?

Funding Acknowledgements

Type of funding sources: None.

Background

Cryoballoon pulmonary vein isolation (CB) is an accepted method for ablation in patients with atrial fibrillation (AF). A three-month blanking period (BP) is commonly used in clinical trials and practice. However, when the optimal BP duration differs in patients (pts) on or off an antiarrhythmic drug (AAD) at time of ablation remains undefined.

Objective

To compare the BP duration in pts undergoing CB while either taking or not taking an AAD.

Methods

We enrolled consecutive pts with AF who had CB PVI while on an AAD. All pts had an implantable loop recorder (ILR). We prospectively followed all pts and determined the time to last AF episode during the 90-day post-PVI BP. This was then correlated with likelihood of having an AF recurrence between 3-12 months post-PVI.

Results

The cohort included 164 pts (66 ± 9 years; 97 [60%] male; 90 [55%] PAF; CHA2DS2-VASc 2.7 ± 1.7). Ablation was performed with 92 (56%) pts taking an AAD, which was stopped at a median of 80 [36, 105] days post-PVI. We defined 4 distinct groups: (1) no AF in 90-day BP (n = 75 [46%]); (2) last AF within 30 days of PVI (n = 32 [20%]); (3) last AF within 60 days of PVI (n = 17 [10%]); and (4) last AF within 90 days of PVI (n = 40 [24%]). Following the 90-day BP, 81 (49%) pts had a recurrence of AF. Long-term freedom from recurrent AF was similar in pts who did and did not use an AAD, irrespective of BP duration (Figure).

Conclusion

Our data suggest that the optimal BP duration in AF patients undergoing CB PVI while taking an AAD is 30 days. An AF recurrence after 30 days is associated with a very high likelihood of recurrent AF during longer-term follow-up, irrespective of whether an AAD is being used or not. Abstract Figure.

The impact of mating systems and dispersal on fine-scale genetic structure at maternally, paternally and biparentally inherited markers

For decades, studies have focused on how dispersal and mating systems influence genetic structure across populations or social groups. However, we still lack a thorough understanding of how these processes and their interaction shape spatial genetic patterns over a finer scale (tens-hundreds of metres). Using uniparentally inherited markers may help answer these questions, yet their potential has not been fully explored. Here, we use individual-level simulations to investigate the effects of dispersal and mating system on fine-scale genetic structure at autosomal, mitochondrial and Y chromosome markers. Using genetic spatial autocorrelation analysis, we found that dispersal was the major driver of fine-scale genetic structure across maternally, paternally and biparentally inherited markers. However, when dispersal was restricted (mean distance = 100 m), variation in mating behaviour created strong differences in the comparative level of structure detected at maternally and paternally inherited markers. Promiscuity reduced spatial genetic structure at Y chromosome loci (relative to monogamy), whereas structure increased under polygyny. In contrast, mitochondrial and autosomal markers were robust to differences in the specific mating system, although genetic structure increased across all markers when reproductive success was skewed towards fewer individuals. Comparing males and females at Y chromosome vs. mitochondrial markers, respectively, revealed that some mating systems can generate similar patterns to those expected under sex-biased dispersal. This demonstrates the need for caution when inferring ecological and behavioural processes from genetic results. Comparing patterns between the sexes, across a range of marker types, may help us tease apart the processes shaping fine-scale genetic structure.

Evaluation of the pylorus with concurrent intraluminal pressure and EndoFLIP in patients with nausea and vomiting

BACKGROUND

Nausea and vomiting occurs in gastroparesis due to diabetes mellitus or unknown causes. The aim of this study was to compare (i) pyloric distensibility to pyloric manometric pressure in patients with nausea and vomiting and (ii) to correlate distensibility with delays in gastric emptying.

METHODS

Sleeve manometry and EndoFLIP were performed sequentially during the same endoscopy on 114 patients with nausea and vomiting (47 with diabetes mellitus and 67 with idiopathic cause) after a standardized gastric emptying study. The sleeve manometer was positioned fluoroscopically, and the EndoFLIP was placed endoscopically. Manometric pressure using a water-perfused catheter and distensibility using an EndoFLIP filled with 40 cc of saline were measured from the pylorus.

KEY RESULTS

The basal pyloric pressure was elevated (>10 mmHg) in 34 patients and was normal in 80 patients. The basal and peak pressures were similar in patient with normal and delayed gastric emptying (p > 0.05). There was a significant decrease in distensibility (8.0 ± 1.0 mm(2) /mmHg) in patients with gastric retention (>20% at 4 h) compared with patients (12.4 ± 1.4 mm(2) /mmHg) (p < 0.01) with normal gastric retention (<10%). Pressure measurements from the sleeve manometer and the EndoFLIP correlated (r = 0.29) (p < 0.002), and increased EndoFLIP balloon pressure (19.4 ± 1.4 mmHg) (p < 0.01) was associated with a severe delay in gastric emptying.

CONCLUSIONS & INFERENCES

Elevated basal pyloric pressure occurs in 42% of patients with nausea and vomiting and delayed emptying. Decreased pyloric distensibility occurs with nausea, vomiting, and delayed gastric emptying. The EndoFLIP is a useful tool in the evaluation of pyloric function in symptomatic patients.

Fine-scale refuges can buffer demographic and genetic processes against short-term climatic variation and disturbance: a 22-year case study of an arboreal marsupial

Ecological disturbance and climate are key drivers of temporal dynamics in the demography and genetic diversity of natural populations. Microscale refuges are known to buffer species' persistence against environmental change, but the effects of such refuges on demographic and genetic patterns in response to short-term environmental variation are poorly understood. We quantified demographic and genetic responses of mountain brushtail possums (Trichosurus cunninghami) to rainfall variability (1992-2013) and to a major wildfire. We hypothesized that there would be underlying differences in demographic and genetic processes between an unburnt mesic refuge and a topographically exposed zone that was burnt in 2009. Fire caused a 2-year decrease in survival in the burnt zone, but the population grew after the fire due to immigration, leading to increased expected heterozygosity. We documented a fire-related behavioural shift, where the rate of movement by individuals in the unburnt refuge to the burnt zone decreased after fire. Irrespective of the fire, there were long-term differences in demographic and genetic parameters between the mesic/unburnt refuge and the nonmesic/burnt zone. Survival was high and unaffected by rainfall in the refuge, but lower and rainfall-dependent in the nonmesic zone. Net movement of individuals was directional, from the mesic refuge to the nonmesic zone, suggesting fine-scale source-sink dynamics. There were higher expected heterozygosity (HE ) and temporal genetic stability in the refuge, but lower HE and marked temporal genetic structure in the exposed habitat, consistent with reduced generational overlap caused by elevated mortality and immigration. Thus, fine-scale refuges can mediate the short-term demographic and genetic effects of climate and ecological disturbance.

Models of systemic lupus erythematosus: development of autoimmunity following peptide immunizations of noninbred pedigreed rabbits

Reported in this study are the initial results from studies to develop rabbit models of systemic lupus erythematosus (SLE) by immunizations using two distinct peptides on branched polylysine backbones (multiple Ag peptide)-peptides. Eleven rabbits received a peptide from the Sm B/B' spliceosomal complex previously shown to be immunogenic in rabbits, and 13 rabbits received a peptide from the rabbit N-methyl-d-aspartate receptor NR2b. All 24 animals in different generations of pedigreed, noninbred rabbits produced peptide-specific responses. Anti-nuclear autoantibody responses, including anti-dsDNA, were seen in 17 of 24 rabbits. To date, two rabbits have been observed to have seizure-like events and a third nystagmus. A model for eliciting development of SLE in genetically related yet heterogeneous rabbits may more closely resemble development of human SLE than do some models in inbred mice. Through selective breeding, it may also ultimately provide additional information about the genetics and etiology of SLE and serve as a model for assessing new treatment options.

Mitral valve surgery via a right anterior mini-thoracotomy with central aortic cannulation and no endoscopic assistance

BACKGROUND

A variety of techniques have been described to reduce surgical access in mitral valve surgery: Mini-sternotomy (Gundry) involves partial division of the sternum while the right anterior mini-thoracotomy approaches described involve either Port Accesstradmark; (Heartport, Redwood City, CA), indirect endoscopic techniques (Chitwood) and more recently, robotic techniques (Intuitive Surgicaltradmark;). This report describes a simplified approach that "borrows" aspects from several techniques.

METHODS

Using currently available technology, a simplified technique to perform mitral valve surgery (MVST) has been developed. MVST eliminates the need for endoscopic assistance and femoral arterial cannulation. The results of 50 of these patients were analyzed and compared with those of 66 patients who had isolated mitral valve surgery via a conventional approach (MVCS) over the same five-year interval.

RESULTS

Between January 1, 1995 and December 31, 2000, 50 patients had mitral valve surgery performed with a simplified technique (MVST). Twenty-six (52%) of the MVST patients underwent mitral valve replacement and 24 (48%) underwent mitral valve repair. There were no in-hospital deaths in the MVST group, compared to a death rate of 7.1% in the MVCS group. There were no strokes and no perioperative myocardial infarctions in the MVST group. Average ICU stay was 3.4 days (1 day shorter than the MVCS group) and average hospital stay was 8.1 days, which was significantly less than the 12.5 day length of stay for the patients having MVCS (p<0.01). Blood was utilized in 36% of the MVST patients, compared to a 55% rate in the MVCS group. There were no wound infections in the MVST group. Two patients did develop bloody effusions requiring thoracentesis. Antegrade blood cardioplegia was used in 35 (70%) of the MVST patients. Antegrade and retrograde blood cardioplegia was used in 15 (30%) patients. Average cross-clamp time in the MVST group was 70 minutes compared to 85 in the MVCS group (p<0.05) and the average pump run was 98 minutes in the MVST group compared to 112 for the MVCS group (p=0.08).

CONCLUSION

Mitral valve surgery using a simplified, less invasive technique can be successfully and safely performed in selected patients, resulting in less blood utilization and shorter hospital length of stay, with a cosmetic result that rivals that of robotically assisted techniques.

Declawing of neonatal rabbits destined for use in animal biosafety level 4 containment studies

To protect personnel and protective outerwear from damage by scratching, rabbits to be housed in an Animal Biosafety Level 4 (ABSL4) facility are declawed routinely. The objective of the study presented here was to establish a procedure for declawing all four feet of neonatal rabbits in preparation for use in ABSL4 studies. Combining procedures conducted in private veterinary practice to remove dewclaws of canine pups with those used to declaw cats, we declawed rabbit kits at 3 to 8 days of age. Declawing neonates was believed to be advantageous because they are non-ambulatory, have soft, cartilaginous digits, and do not have extensive hair growth. These features resulted in decreased surgical preparation and surgery time, minimal bleeding, and minimal aftercare. The optimal age for declawing a litter was 6 or 7 days. Declawing of neonatal rabbits is relatively simple and efficient to perform and offers advantages over declawing of older animals. By using the method described, rabbits can be introduced into ABSL4 facilities by 12 weeks of age with confidence that nail regrowth will not occur.

Coronary artery bypass surgery on small patients

Little research exists on the outcome of smaller patients who undergo coronary artery bypass graft surgery. The purpose of this study was to evaluate the outcomes of cardiac surgery in smaller patients (males with body surface area of 1.6 square meters or less, and women with 1.5 meters or less). A consecutive series of 4,358 patients undergoing bypass surgery was evaluated. Of these, 246 (5.6%) were classified as small patients. Smaller patients were more likely to be women, older and of Asian ethnicity. They were less likely to have undergone a prior cardiac surgery. Smaller patients were less likely to receive an arterial conduit (74% versus 99%; p<0.00001). Rates of post-surgery complications differed between small and normal size patients, with smaller patients more likely to require prolonged ventilator support (p <0.05), more likely to have acute renal failure (p<0.0001), more transfusions and re-operation for bleeding (p<0.05), higher death rate (5.7% versus 2.6%; p<0.01) and longer length of hospital stay (11.4 versus 8.3 days; p<0.00001). In multivariate analyses evaluating factors related to death, emergent surgery, poor ejection fraction and older patient age were independently related to mortality. Small body surface area was not an independent predictor. The results of this study indicate that smaller patients do have poorer outcomes associated with coronary artery bypass surgery. However, 90% of the smaller patients did have an event-free surgery. Surgeons may need to monitor these patients more closely and anticipate the increased risk and cost that is associated with this group.

A process for ensuring optimal cardiovascular intervention and identifying candidates for glycoprotein IIb/IIIa receptor inhibitor therapy

Data from trials with glycoprotein (GP) IIb/IIIa receptor inhibitors have led to a new standard of care for patients with unstable angina or non-wave myocardial infarction (MI) who are undergoing percutaneous coronary intervention. Additional data are necessary to compare patient responses to various GP IIb/IIIa agents in a nontrial setting with results from clinical trials. Seton Medical Center has designed a database to accommodate this task. Data from >20,000 patients have been collected since 1979 and the interventional experience from the years 1997 through 1999 has been analyzed for patients who were candidates for receiving these agents. The data are being used to evaluate the outcomes of therapy and to devise models that can stratify patients according to risk, thereby ensuring optimal cardiovascular intervention and choice of the most cost-effective GP IIb/IIIa inhibitor agent.

Recent improvement in results of coronary bypass surgery in octogenarians

BACKGROUND

Because of concerns regarding the cost-effectiveness of coronary artery surgery in patients 80 years and older, a review of a large experience is appropriate.

METHODS

The records of 404 consecutive patients 80 years of age or older having isolated coronary bypass surgery (CABG) from 1985 through 1996 were reviewed. Patients were divided equally into an early and later group. Hospital mortality, complications including major arrhythmias, wound infections and separations, re-explorations, peri-operative Q-wave myocardial infarctions, major organ dysfunction, stroke, time to extubation, post-operative hospital (LOS) and intensive care unit (ICU) lengths of stay were compared. A logistic regression risk model was used to assess the relative contributions of improved technique versus more favorable patient selection.

RESULTS

Comparison of the two groups revealed the following: overall hospital mortality decreased from 12.9% to 5.4% (p = 0.003), more markedly so with elective procedures where hospital mortality decreased from 8.1% to 1.2% (p = 0.04). There were significant decreases in time to extubation (2.8 +/- 9.3 days versus 1.2 +/- 2.8 days; p = 0.02), post-operative intensive care unit stay (4.9 +/- 7.1 days versus 2.9 +/- 3.7 days; p = 0.0004), post-operative complication rate (34.2% versus 22.8%; p = 0.03), and post-operative hospital length of stay (14.2 +/- 14.7 days versus 9.8 +/- 9.8 days; p = 0.0005). Post-operative stroke decreased from 7.4% to 5.9%. Mean estimated risk for the two groups was 8.2 +/- 10.2% versus 8.2 +/- 11.4%.

CONCLUSION

Coronary surgery can be performed with acceptable risk in octogenarians. Results have improved over the past few years. This improvement is probably not attributable to patient selection.

Intrinsic and required dynamics of a simple bat-ball skill

Three experiments investigated the coordination dynamics of a simple bat-and-ball skill: cyclically striking a ball suspended by a string with a pendular bat. The relative phase phi between the bat and ball is dictated by the potential function V(phi) = k sin phi and the difference delta omega in their uncoupled frequencies. For various delta omega, phi and its standard deviation were measured in the absence of any environmental restraints (intrinsic dynamics) and when the ball had to reach resistive or nonresistive targets at set distances (required dynamics). Results support the dynamical theory of coordination patterns (G. Schöner & J.A.S. Kelso, 1988a, 1988c), particularly the hypothesis that required dynamics are understandable as the addition of terms to the potential governing the intrinsic dynamics.

Making the constraints visible: testing the ecological approach to interface design

A haemodynamic monitoring and control task was used to evaluate the ecological approach to interface design for complex high-technology environments. Guidelines proposed by Bennett and Flach (1992) were used to design multilevel displays that made visible (a) anatomical constraints, and (b) causal constraints on haemodynamic systems. These displays were compared with a traditional display that showed pressure and flow values in five separate graphs. Simulations of clinical problems were generated by a computer model and presented in an interactive computer environment. Critical care nurses and nursing students observed changes in pressures and flow corresponding to certain disease states and corrected those states using simulated drugs. For both groups, speed and accuracy were progressively improved by the enhanced, multilevel displays.

High-speed rotational atherectomy: six-month serial quantitative coronary angiographic follow-up

One hundred twenty-three patients treated with high-speed rotational atherectomy (HSRA) were restudied 6.9 +/- 1.2 months later. At the follow-up, the number of focal concentric lesions increased from 32.2 percent to 63.0 percent, p<0.01, with decrease of type C lesions from 54.8 percent to 30.8 percent, p<0.05. Comparison of the degree of the net gain (NG) showed more severe baseline lesions in the high-gain group (NG >20 percent) compared with the moderate-gain group (20 percent > NG > 0 percent) and to the loss group (minimal luminal diameter [MLD] 0.8 +/- 0.4 mm vs 1.0 +/ 0.4 mm, p<0.05; and 1.2 +/- 0.5 mm; p<0.01, respectively). Highest initial gain (36.5 percent +/- 26.2 percent vs 24.5 percent +/- 18.1 percent; p<0.015; and 19.0 percent +/- 23.2 percent; p<0.001) as well as lowest late loss (1.8 percent +/- 21.7 percent vs 14.0 percent +/-18.4 percent; p<0.01 and 28.1 percent +/- 25.0 percent; p<0.01) were found in the high NG group. A higher interaction between burr and atheroma resulted in the lowest restenosis rate of 6 percent.

Outcome of narrowing related side branches after high-speed rotational atherectomy

High-speed rotational atherectomy (HSRA) is advocated for calcified and diffusely narrowed coronary arteries. There are often side branches involving these kinds of lesions. The presence of significant lesion-related side branches has been considered a relative contraindication to rotational atherectomy. This study was performed to determine the rate, predictors, and outcome of side branch occlusion after HSRA. The angiograms of 418 patients were examined with 320 side branches in 240 target vessels of > or = 1 mm in diameter being identified. Vessels were scored as either perfused (Thrombolysis In Myocardial Infarction 2 or 3 flow) or occluded (Thrombolysis In Myocardial Infarction 0 or 1 flow before and after the procedure. A detailed quantitative angiographic analysis was performed on a total of 108 side branches including all cases of branch occlusion. Clinical outcomes were determined in all cases with side branch loss. There were 24 occlusions in 21 patients after the procedure, giving a rate of branch loss of 7.5%. Follow-up angiography of > or = 24 hours was available for 13 of the occluded branches and 12 were found to be patent. In the 21 patients with branch occlusion, 6 sustained a myocardial infarct (of which 5 were non-Q-wave), 2 underwent coronary artery bypass grafting, and 2 died. There are frequently lesion-associated side branches in the types of vessels to undergo HSRA. These branches remained patent 92.5% of the time, with occlusion occurring infrequently and usually being transient. When occlusion did occur, there was a 29% incidence of myocardial infarction.

Effects of technique modification on immediate results of high speed rotational atherectomy in 710 procedures on 656 patients

Seven hundred ten high speed rotational atherectomy (HSRA) procedures were performed in a single consecutive series of 656 patients. Stand alone HSRA was performed in 253 patients (35%). HSRA with adjunctive low pressure (< or = 2 ATM) balloon angioplasty (LP BA) was performed in 221 patients (31%), and HSRA with adjunctive high pressure (> or = 4 ATM) balloon angioplasty (HP BA) was performed in 236 patients (34%). Prognostically unfavorable Type B2 and C lesions dominated the study group (74.7%). Procedural success rate was 96%. Emergency coronary artery bypass surgery was performed in 1.4% of cases, Q wave myocardial infarction occurred in 3.4% and death, related to procedure, was consequent in 0.5% of cases. Incidence of flow limiting dissections was 3.1%, distal spasm was 5.3%, and "no reflow" phenomenon was 1.8%. The recent technique modifications included continuous advancer/guiding catheter infusion of the nitroglycerin-verapamil mixture, limitation of duration of lesion engagement by the burr, stepwise increase in the burr size, decrease of rotational speed, and strict control of rpm drop during lesion ablation. Evolution of the interventional technique involved trends towards decrease of the use of HP BA in conjunction with steady increase in the percentage of SA and LP BA procedures over time. These technique changes resulted in complete absence of "no reflow" in 1994, as well as a generalized decrease in overall coronary vascular reactivity from all burr passes.

Role of intraaortic balloon pump counterpulsation in high risk coronary rotational atherectomy

OBJECTIVES

This study sought to evaluate the role of intraaortic balloon pump counterpulsation in preventing hemodynamic instability and promoting a successful outcome during percutaneous transluminal coronary rotational atherectomy in high risk patients.

BACKGROUND

The application of rotational atherectomy has widened to include patients with complex lesions and left ventricular dysfunction. Although intraaortic balloon pumping has been successfully used to provide hemodynamic support during balloon angioplasty, its role in high risk rotational atherectomy has not yet been defined.

METHODS

In a retrospective review of 159 consecutive high risk patients who underwent rotational atherectomy, 28 had an intraaortic balloon pump placed electively before the procedure (Group 1) whereas 131 did not (Group 2).

RESULTS

Group 1 was older and more likely to have multivessel disease and left ventricular dysfunction. Augmented diastolic pressure was maintained > 90 mm Hg in all Group 1 patients, and significant procedure-related hypotension was encountered in nine Group 2 patients, requiring an emergency intraaortic balloon pump in five. Procedural success was achieved in all 28 patients in Group 1 and in 118 in Group 2 (p = 0.07). Slow flow occurred in 18% and 17% of Group 1 and 2 patients, respectively. Among patients with slow flow, non-Q wave myocardial infarction occurred only in Group 2 (0% vs. 27%). On multivariate analysis, elective intraaortic balloon pump placement was the only variable to correlate with a successful procedure uncomplicated by hypotension (p < 0.05). Hospital stay and vascular complications were similar in both groups.

CONCLUSIONS

Elective placement of an intraaortic balloon pump before coronary rotational atherectomy in selected high risk patients promotes both procedural hemodynamic stability and a successful outcome.

Dyslipoproteinemias in atherosclerosis, thrombosis and restenosis after coronary angioplasty

Lipids play a vital role in normal metabolic function in mammals. However, dyslipoproteinemias have been implicated in the pathophysiologic process of atherogenesis, thrombogenesis and restenosis after interventional procedures. Lipoproteins provide important chemical linkages among these three complex phenomena. Lipoproteins participate in atherogenesis and play a major role in plaque fissuring, the pathophysiologic common denominator of acute ischemic syndromes. Thrombogenesis is majoraly affected by the action of lipids on platelets, coagulation and fibrinolysis. LDL tend to destabilize platelet membrane activity, macrophages, endothelial and smooth muscle cell function; HDL tend to reverse these abnormalities. The metabolism of arachidonic acid, a metabolite of the essential polyunsaturated lipoprotein, linoleic acid, is integral to platelet and endothelial cell membrane formation, via the cyclooxygenase-prostanoid pathway. Arachidonic acid also is metabolized by the lipoxygenase-leukotreine pathway in neutrophils and monocytes. The relationship of dyslipoproteinemias (increased LDL and Lp(a); decreased HDL) to restenosis after angioplasty has been reported, though there is not universal agreement about causality. Lipid lowering regimens and other pharmacotherapy have had favorable effect slowing the rate of atherogenesis, decreasing the frequency of cardiac events (perhaps by "stabilizing" vulnerable plaques) and causing regression in some atheromata. The salutary effect of lipid-lowering agents upon the incidence of restenosis after angioplasty is problematic. Some investigators have found a statistically significant correlation, while others have not; but studies have not been standardized. In conclusion, the study of lipid metabolism across a wide range of physiochemical activities and the interaction of these phenomena describe complex, genetically determined linkages which instruct (and often humble) investigators in their study of lipids in health and disease.

Arterial conduits in emergency coronary artery surgery

The internal thoracic artery (ITA) is considered to be the conduit of choice for coronary bypass (CABG), but there has been some reluctance to utilize the ITA for revascularization in emergency situations. In a 9-year retrospective analysis from 1986 through 1993, 484 patients had emergency CABG, 237 were not associated with failed PTCA (noninstrumented) and 247 were within 24 hours of PTCA (instrumented). About 62% of noninstrumented and 49.3% of instrumented patients received one or more ITA grafts, the others receiving only saphenous vein grafts (SVGs). Those who received an ITA graft tended toward male sex, better ejection fraction, and a generally lower clinical risk score. Instrumented patients tended toward a lower incidence of diabetes and left main coronary disease, higher ejection fraction, and lower clinical risk score than noninstrumented patients. The postoperative results were not significantly different between ITA and SVG groups with respect to new Q waves, need for reexploration, sternal wound infection, respiratory complications, or stroke. However, ITA patients more often had an event-free postoperative course, received fewer blood transfusions, and experienced fewer cardiac deaths (2.7% vs 9.4%, p < 0.01). There were few obvious differences in postoperative results between instrumented and noninstrumented patients. These results indicate that the ITA can be used for emergency CABG in selected patients with good results.

Quantitative left ventriculography: methods of assessment of the regional contractility

To compare different approaches to the quantitative analysis of regional left ventricular (LV) function, six different protocols with various long axis definitions, with or without alignment, with radial or hemiaxial segmental definitions were used. Study group consisted of 20 patients with single vessel coronary artery disease after Q-wave anterior myocardial infarction (MI) and 20 patients after Q-wave diaphragmatic MI. Control group consisted of 100 patients. Analytic protocol with the long axis drawn between the apex of the LV and the center of aortic valve plane, radial coordinate system originating from the midpoint of the long axis and alignment of the long axes in systole and diastole, was found to be most sensitive and specific for detection of both anterior and diaphragmatic contraction abnormalities. Original method to measure both severity and length of the regional contraction abnormality is suggested.

Comparative study of the angiographic morphology of coronary artery lesions treated with PTCA, directional coronary atherectomy, or high-speed rotational ablation

To evaluate trends in morphology-based intervention selection, series of 110 consecutive procedures of each of three devices, percutaneous transluminal balloon coronary angioplasty (PTCA), directional coronary atherectomy (DCA), or high-speed rotational ablation (HSRA), were reviewed. PTCA was used mainly in discrete, concentric, smooth, ACC/AHA type A and B1 lesions. PTCA was used less frequently on a bend, branching points or in calcified lesions. Using PTCA as a reference, DCA was used more often for the treatment of discrete, proximal, eccentric, and noncalcified lesions, often complicated with thrombus and located on straight segments. HSRA was used more frequently in diffuse, calcified multiple complicated and B2+C type lesions with frequent side branches and bend points. These results suggest that directional atherectomy and rotational ablation may be helpful in expanding the capacity of the operator to approach prognostically unfavorable lesions.

Triple vessel revascularization: coronary angioplasty versus coronary artery bypass surgery: initial results and five-year follow-up. Comparative costs and loss of working days and wages

OBJECTIVES

The purpose of this study was to compare early and late outcomes in patients undergoing PTCA or CABG for triple vessel disease.

BACKGROUND

Although early results of PTCA/CABG randomized trials have recently become available, at present little data exists on long-term medical and socioeconomic effects of these treatment modalities in patients with triple vessel revascularization.

METHODS

During 1986-87, 76 patients undergoing triple vessel PTCA and 85 patients having triple vessel CABG were selected from a consecutive series of patients having multivessel revascularization. Initial results and 5 year outcome, hospital stay and charges and out-of-work time were assessed from prospectively collected data.

RESULTS

Clinical and morphological factors were similar in the PTCA and CABG groups. Hospital success and complications were also similar, except for higher mortality in the CABG cohort (0 vs. 3.5%). Five year follow-up showed no differences in survival, nonfatal infarction and angina-free status; however, there was a difference in need for repeat revascularization (PTCA 55.4% vs. CABG 6.3%, p less than 0.001). Repeat PTCA accounted for 49% of the revascularization in the PTCA cohort. Crossovers were similar (PTCA[CABG 6.8%; CABG[PTCA 6.3%, pNS). Predictors of late death in the entire population were female gender (p less than 0.0001), diabetes (p<0.05) and depressed LVEF (p less than 0.05). The choice of revascularization procedure (PTCA vs. CABG) was not an independent predictor of late death or MI. Analysis of initial hospital charges showed a 2:1 advantage in favor of PTCA but this advantage was lost in late followup due to the need for repeat revascularization in the PTCA group. However, the PTCA cohort lost fewer working days than CABG patients (3017 vs 5874 days) and therefore, lost less wages ($7,022 vs. $14,685).

CONCLUSIONS

The study shows that for selected triple vessel disease patients, PTCA and CABG results are comparable after 5 years, though repeat revascularization (mainly due to restenosis) was necessary in the PTCA group to maintain these favorable results. After 5 years, hospital charges are similar in the 2 groups, though out-of-work time and lost wages were 2:1 in favor of PTCA.

Making the relationships visible: testing alternative display design strategies for teaching principles of hemodynamic monitoring and treatment

A hemodynamic monitoring and control task was used to explore the utility of perceptually based displays to teach basic hemodynamic principles. The baseline display showed discrete values of key hemodynamic data elements. Alternative displays showed (a) anatomical relationships between those elements, and (b) causal constraints. Critical care nurses and student nurses used simulated "drugs" to correct simple hemodynamic disturbances using the three displays. Showing the anatomic constraints on pressure and flow improved treatment coordination by novices. Showing how etiological factors related to symptoms shortened the time required to reach a criterion level of performance and improved treatment coordination for both novices and experts.

Coronary stenting with a new ultra-short balloon expandable device: early and late animal results

The early and late effects of a new balloon-expandable coronary stent (Boneau II) were studied in 16 adult mongrel dogs. Thirty-three balloon-expandable stents were deployed using standard transfemoral coronary angioplasty technique. Single stents were placed in eight dogs and multiple (two to four) stents were placed in eight dogs. Intravenous heparin (3,000 units) was administered at the beginning of the procedure. Aspirin, dipyridamole, dextran, and warfarin were not administered before or after the procedure. All stent deployments were successful. Angiographic or pathologic examinations were performed within 24 hr of deployment on two of the dogs, at 2 weeks on two of the dogs, at 2 months on three of the dogs, at 6 months on six of the dogs, and at 1 year on three of the dogs. All successfully deployed stents were noted to be widely patent. There was no evidence of side-branch vessel occlusion. There was no evidence of acute or late vessel thrombosis. Histologic examination at 2 months showed a mean intimal thickness of 153 microns. The stainless steel Boneau II coronary stent is relatively short and easily deployed. This balloon-expandable coronary stent was successfully deployed in normal canine arteries without the use of anticoagulation or antiplatelet therapy before or after the procedure. The Boneau II intracoronary stent has a very low thrombogenic potential in dogs.

High speed rotational atherectomy in coronary artery disease

Despite major advances in its diagnosis and management, coronary artery disease remains the major cause of death accounting for 45.3 percent of all deaths in the United States. One of the major milestones in the treatment of coronary artery disease has been the introduction of non-surgical revascularization in the form of percutaneous transluminal coronary angioplasty by Andreas Gmentzig in 1977. In the early years, PTCA could only be performed in proximal, discrete, non-calcified lesions. Over the last decade, major advances in the catheter, balloon and guide wire technology as well as increased operator experience extended the benefits of PTCA to patients with more complex lesions and multivessel coronary artery disease. Although the initial impetus for the development of newer devices has been to address the problem of restenosis, they are proving to be useful in treating lesions that are inadequately treated or subject to increased incidence of complications. The high speed rotational atherectomy is a valuable addition with its ability to treat long, calcified lesions. This report will describe the technical aspects of the Rotablator®, the procedure of high speed rotational atherectomy and its clinical applications.

Late outcome of multivessel coronary artery disease after angioplasty or bypass surgery

Background. Results from randomized trials to determine optimal treatment for patients with multivessel coronary disease are not yet available. Thus, the early and late outcomes of 191 PTCA and 221 CABG patients done in 1985-86 were evaluated. Methods and Results. CABG patients selected had more coronary risk factors and more severe coronary artery disease compared to PTCA patients. Comparison of the initial outcome showed that clinical success without major cardiovascular events was similar (93.7% for PTCA vs. 90.0% for CABG; p=n.s.). Five year followup was obtained in 99.0% of PTCA patients and 94.4% of CABG patients. In the PTCA group, 89.8% were alive, 4.8% had sustained an MI, and repeat revascularization was required in 46.8%. In the CABG group, 87.1% were alive, 3.2% had had a MI, and 3.5% required repeat revascularization. Statistical comparison demonstrated no difference between the groups in survival or late cardiac events, but rate of repeat revascularization was significantly higher for PTCA patients (p less than 0.0001). Incompleteness of revascularization (p<0.01) was independently associated with an increased need for repeat revascularization in the PTCA group. In the CABG group, depressed left ventricular function (p less than 0.001) and female sex (p<0.01) were associated with lower survival rates. An analysis of cost per patient showed that the strategies were comparable. Conclusions. PTCA and CABG in multivessel disease patients have similar early results and comparable rates of survival and late cardiac events. Significantly more repeat revascularization is required in PTCA patients to maintain these results.(ABSTRACT TRUNCATED AT 250 WORDS)

The evolution of a clinical database to evaluate the treatment of coronary artery disease

BACKGROUND

The field of invasive cardiology has evolved rapidly since the initial use of catheters for treatment of coronary artery disease in the late 1970's. The pace of this change coupled with the complexity of the clinical setting and proliferation of devices and drugs used for therapy have made it extremely difficult to construct and maintain a viable clinical database.

METHODS

Using a standard hardware and software system with the direct clinical input from a multidisciplinary team of physicians, nurses and biostatisticians, a clinical database was developed that is capable of tracking complex in-hospital and longterm follow-up data in patients undergoing treatment of coronary artery disease.

RESULTS

The database has provided the basis for in-depth analysis of angioplasty results in patients with vessels and lesions of varying morphology, showing greater than 90% success in most complex lesion morphology using contemporary balloon technology and/or new devices. Longterm analysis (14 years) of patients after angioplasty has demonstrated that 76% survived without major cardiac events. Other analyses of various clinical and morphologic subsets have shown favorable results with angioplasty. The databases for angioplasty and coronary bypass surgery have been combined, showing comparable survival and freedom from cardiac events in multivessel disease patients treated with these procedures.

CONCLUSIONS

The development of a dynamic and clinically relevant database that has evolved has contributed valuable information to the understanding and effective management of patients with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and antimicrobial activity of DNA-gyrase inhibiting derivatives of 4-oxo-1,4-dihydro-3-pyridinecarboxylic acid

A series of 6-substituted-1-aryl-4-oxo-1,4-dihydronicotinic acids were synthesised as monocyclic analogues of the quinolones. The 6-(2-aryl-1-methylethenyl)- and of the 6-(2-arylethenyl)-substituted compounds were shown to possess antibacterial properties that correlate with DNA gyrase inhibitory activity. Differently from the quinolones the antimicrobial activity of the compounds of this study is predominantly against Gram positive strains. The structure-activity relationships ascertained for these monocyclic compounds differ from those established for the quinolones.

Coronary rotational ablation: initial experience in 302 procedures

OBJECTIVES

The aim of this study was to assess the utility of percutaneous transluminal coronary rotational ablation in the treatment of coronary artery disease.

BACKGROUND

Although numerous advances have been made in the treatment of coronary artery disease, there are lesions with complex morphology that are not amenable to current intravascular therapy.

METHODS

A consecutive series of 242 patients having 302 coronary rotational ablation procedures was analyzed. One hundred nineteen (49%) of the patients had previously undergone attempted coronary angioplasty, which was unsuccessful in 31 patients (13%). The left ventricular ejection fraction was normal in 196 patients (81%). The ablation procedure was attempted in 308 vessels and 346 lesions. Of the 346 lesions treated, 26 (7.5%) were classified as American College of Cardiology/American Heart Association type A, and 320 (92.5%) as either type B or type C.

RESULTS

Procedural success was achieved in 284 (94%) of the 302 procedures and 330 (95.4%) of the 346 lesions in which ablation was attempted. Five procedures (1.7%) were unsuccessful, but no cardiac event occurred during the hospital stay. A major cardiac event occurred in 13 cases (4.3%); 9 (3%) of these complications were due to the ablation procedure. Six patients sustained a Q wave myocardial infarction alone, two had a Q wave infarction and required emergency surgery and one needed emergency surgery but did not have a Q wave infarction. No procedural deaths were attributed to the ablation procedure. Follow-up has been obtained in 182 of the 242 patients at a mean interval of 9 +/- 5 months. Of the 182 patients, 174 (95.6%) were alive and free of myocardial infarction. Angiographic follow-up is available thus far in 87 patients. By combining angiographic and clinical outcome, an overall estimated restenosis rate of 37.4% (68 of 182) was calculated.

CONCLUSIONS

These data suggest that coronary rotational ablation can be performed on lesions with a variety of morphologic features with high initial success rates. The overall rate of restenosis is similar to that of balloon angioplasty.

Rotational ablation of balloon angioplasty failures

In this series, we evaluated the use of rotational ablation in stenoses that were previously refractory to balloon angioplasty. Forty-one stenoses were treated; in 26, the balloon did not adequately expand within the lesion and in 15 the balloon could not be delivered to the stenosis. Rotational ablation was technically successful in 40 of 41 (97.6%) of the lesions attempted. Twenty-four patients have been followed (mean time = 9 +/- 5 months) and the restenosis rate was similar to that of balloon angioplasty. Rotational ablation appears well suited and may be the treatment of choice for heavily calcified, severely angulated, and diffusely diseased vessels.

Lesion morphology and coronary angioplasty: current experience and analysis

From July 1, 1990 to February 28, 1991, 533 consecutive patients with 764 target vessels and 1,000 lesions underwent coronary angioplasty. Procedural success was achieved in 92.3%, untoward (major cardiac) events occurred in 3% (0.8% myocardial infarction, 1.3% emergency coronary bypass grafting and 0.9% both; there were no deaths). An unsuccessful uncomplicated outcome occurred in 4.7%. Lesion analysis using a modified American College of Cardiology/American Heart Association classification system showed that 8% were type A, 47.5% were type B and 44.5% were type C (36% of type B and 11% of type C were occlusions). Angioplasty success was achieved in 99% of type A, 92% of type B and 90% of type C lesions (A vs. B, p less than 0.05; B vs. C, p = NS; A vs. C, p less than 0.01). Untoward events occurred in 1.2% of type A, 1.9% of type B and 2% of type C lesions (p = NS). An unsuccessful uncomplicated outcome occurred in 0% of type A, 6% of type B and 7% of type C lesions (A vs. B, p less than 0.05; B vs. C, p = NS; A vs. C, p less than 0.05). Among the unsuccessful uncomplicated outcome group, occlusion occurred in 49%: 38% of type B and 59% of type C lesions. With B1 and B2 subtypes, success was obtained in 95% and 89.5% and untoward events occurred in 1.5% and 2.3% and an unsuccessful uncomplicated outcome in 3.7% and 8%, respectively. C1 and C2 subtyping showed success in 91% and 86%, untoward events in 1.3% and 6% and an unsuccessful uncomplicated outcome in 7.5% and 8.5%, respectively. Among the 764 vessels, success was obtained in 89.5% and untoward events occurred in 2.5% and an unsuccessful uncomplicated outcome in 8%. Assessment of lesion-vessel combinations showed a less favorable outcome with type C lesions and combinations of A-B, B-C and multiple (more than three lesions) type B and C vessels. Statistical analysis of morphologic factors associated with angioplasty success included absence of (old) occlusion (p less than 0.0001) and unprotected bifurcation lesion (p less than 0.001), decreasing lesion length (p less than 0.003) and no thrombus (p less than 0.03). The only significant factor associated with untoward events was the presence of thrombus (p less than 0.003). Predictors of an unsuccessful uncomplicated outcome included old occlusion (p less than 0.0001) and increasing lesion length (greater than 20 mm) (p less than 0.001), unprotected bifurcation lesion (p less than 0.05) and thrombus (p less than 0.03).