Decision-Making During Percutaneous Coronary Intervention Guided by Optical Coherence Tomography: Insights From the LightLab Initiative

BACKGROUND

Use of intracoronary imaging is associated with improved outcomes in patients undergoing percutaneous coronary intervention (PCI). Yet, the impact of intracoronary imaging on real-time physician decision-making during PCI is not fully known.

METHODS

The LightLab Initiative is a multicenter, prospective, observational study designed to characterize the use of a standardized optical coherence tomography (OCT) workflow during PCI. Participating physicians performed pre-PCI and post-PCI OCT in accordance with this workflow and operator assessments of lesion characteristics and treatment plan were recorded for each lesion based on angiography alone and following OCT. Physicians were categorized as having low (n=15), intermediate (n=13), or high (n=14) OCT use in the year preceding participation.

RESULTS

Among 925 patients with 1328 lesions undergoing PCI, the prescribed OCT workflow was followed in 773 (84%) of patients with 836 lesions. Operator lesion assessment and decision-making during PCI changed with OCT use in 86% (721/836) of lesions. Pre-PCI OCT use changed operator decision-making in 80% of lesions, including lesion assessment (45%), vessel preparation strategy (27%), stent diameter (37%), and stent length (36%). Post-PCI OCT changed stent optimization decision-making in 31% of lesions. These findings were consistent across strata of physician prior OCT experience.

CONCLUSIONS

A standardized OCT workflow impacted PCI decision-making in 86% of lesions, with a predominant effect on pre-PCI lesion assessment and planning of treatment strategy. This finding was consistent regardless of operator experience level and provides insight into mechanisms by which intravascular imaging might improve PCI outcomes.

Investigating real-world impact of optical coherence tomography workflow-guided coronary interventions: Design and rationale of the LightLab Clinical Initiative

OBJECTIVE

The LightLab Clinical Initiative was designed to examine adoption of optical coherence tomography (OCT) imaging during routine percutaneous coronary intervention (PCI) practice, and enable identification and reduction of barriers to broader adoption of intracoronary imaging in real-world practice.

BACKGROUND

Intracoronary imaging guidance during PCI has been shown to improve clinical outcomes and features as a recommendation in societal guidelines, yet widespread routine adoption remains low. Perceived barriers to utilization include familiarity with, and ability to interpret imaging, concerns over added procedure time and contrast load, alongside a lack of actionable outcome data.

METHODS AND RESULTS

LightLab was a multicenter prospective observational data-gathering project, conducted between January 2019, and June 2021, with 17 participating hospitals and physicians. Data were gathered in real-time, where OCT guidance was employed during PCI using a standardized OCT-guided workflow algorithm, MLD MAX (where MLD stands for plaque Morphology, lesion Length, vessel Diameter and MAX for Medial dissection, stent Apposition, stent eXpansion) which was developed to simplify and integrate information from OCT throughout the PCI procedure. Integration of this workflow/algorithm was implemented through a series of phases, focusing on physician decision-making, efficiency, and safety improvements during the procedure.

CONCLUSIONS

Through real-time, prospective procedural data acquisition in the cardiac catheterization laboratory setting, the LightLab Clinical Initiative demonstrates the impact of a standardized OCT-guided workflow on procedural metrics, including time, contrast use, radiation exposure, as well as financial efficiencies such as device utilization. These results can potentially mitigate underlying concerns over the utility of adoption of intracoronary imaging guidance during PCI.

Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids study

In recent decades, the possibility that use of mobile communicating devices, particularly wireless (mobile and cordless) phones, may increase brain tumour risk, has been a concern, particularly given the considerable increase in their use by young people. MOBI-Kids, a 14-country (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, the Netherlands, New Zealand, Spain) case-control study, was conducted to evaluate whether wireless phone use (and particularly resulting exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF)) increases risk of brain tumours in young people. Between 2010 and 2015, the study recruited 899 people with brain tumours aged 10 to 24 years old and 1,910 controls (operated for appendicitis) matched to the cases on date of diagnosis, study region and age. Participation rates were 72% for cases and 54% for controls. The mean ages of cases and controls were 16.5 and 16.6 years, respectively; 57% were males. The vast majority of study participants were wireless phones users, even in the youngest age group, and the study included substantial numbers of long-term (over 10 years) users: 22% overall, 51% in the 20-24-year-olds. Most tumours were of the neuroepithelial type (NBT; n = 671), mainly glioma. The odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density at the location of the tumour. Further analyses suggest that the large number of ORs below 1 in this study is unlikely to represent an unknown causal preventive effect of mobile phone exposure: they can be at least partially explained by differential recall by proxies and prodromal symptoms affecting phone use before diagnosis of the cases. We cannot rule out, however, residual confounding from sources we did not measure. Overall, our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, the sources of bias summarised above prevent us from ruling out a small increased risk.

Fluid intake and hydration status in obese vs normal weight children

BACKGROUND/OBJECTIVES

Little is known on the relationship between obesity and hydration levels in children. This study assessed whether and by which mechanisms hydration status differs between obese and non-obese children.

SUBJECTS/METHODS

Hydration levels of 86 obese and 89 normal weight children (age: 7-11 years) were compared. Hydration was measured as the average free water reserve (FWR=urine output/24 h minus the obligatory urine output [total 24 h excreted solutes/97th percentile of urine osmolality of children with adequate water intake, that is, 830 mOsm/kg]) over 2 days. Three days of weighed dietary and fluid intakes were recorded. Non-parametric tests were used to compare variables that were skewed and to assess which variables correlated with hydration. Variables mediating the different hydration levels of obese and normal weight children were assessed by co-variance analysis.

RESULTS

Obese children were less hydrated than normal weight peers [FWR=median (IQR): 0.80 (-0.80-2.80) hg/day vs 2.10 (0.10-4.45) hg/day, P<0.02; 32% of obese children vs 20% of non-obese peers had negative FWR, P<0.001]. Body mass index (BMI) z-score (z-BMI) and water intake from fluids correlated with FWR (ρ=-0.18 and 0.45, respectively, both P<0.05). Water intake from fluids completely explained the different hydration between obese and normal weight children [FWR adjusted for water from fluids and z-BMI=2.44 (0.44) hg vs 2.10 (0.50) hg, P=NS; B coefficient of co-variation between FWR (hg/day) and water intake from fluids (hg/day)=0.47, P<0.001].

CONCLUSIONS

Obese children were less hydrated than normal weight ones because, taking into account their z-BMI, they drank less. Future prospective studies are needed to explore possible causal relationships between hydration and obesity.

Medical role of first responders in an urban prehospital setting

Background:

Almost all North American cities have first responder programs. To date there is no published documentation of the roles first responders play, nor of the frequency and type of interventions they perform. Many urban stakeholders question the utility and safety of routinely dispatching large vehicles emergently to calls that may not require their services. Real world data on first responder interventions will help emergency medical services (EMS) directors and planners determine manpower requirements, assess training needs, and optimize dispatch protocols to reduce the rate of inappropriate “code 3” (lights and siren) responses.

Objective:

Our objectives were to determine how often first responders arrive first on scene, to estimate the time interval between first response and EMS response, and to examine the frequency and type of interventions performed by first responders.

Methods:

In a prospective observational study, trained observers were assigned to fire department first responder (FDFR) units. These observers recorded on-scene times for FDFR and EMS units, and documented the performance of first responder interventions.

Results:

FDFRs arrived first on scene in 49% of code 3 calls. They performed critical interventions in 18% of calls attended and 36% of calls where they arrived first. Oxygen administration was the most frequent critical intervention, yet occult hypoxemia was common and compliance with oxygen administration protocols was poor.

Conclusions:

First responders perform critical interventions during a minority of code 3 calls, even when “critical” is defined generously. Many “lights and siren” dispatches are unnecessary. Future research should attempt to identify dispatch criteria that more accurately predict the need for first responder intervention. First responder training and continuous quality improvement (CQI) should focus on interventions that are performed with some regularity, particularly oxygen administration.

Hematopoietic stem cell transplantation for the treatment of autoimmunity in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease that leads to the destruction of the insulin-producing pancreatic b cells. While there is no current cure, recent work in the field of allogeneic hematopoietic stem cell transplantation (HSCT) and the induction of mixed chimerism, a state in which multilineage hematopoietic populations of both recipient and donor co-exist, has demonstrated that it is possible to provide protection from disease onset, as well as reverse the autoimmune state in spontaneously diabetic mice. Furthermore, the establishment of mixed chimerism induces donor-specific tolerance, providing the potential to normalize glucose regulation via pancreatic islet transplantation without the requirement of life-long immunosuppression. Current studies are aimed at understanding the mechanisms involved in both the reversal of autoimmunity and the induction of tolerance, with the aim of moving this promising approach to curing T1D into the clinic.

Protective Effect of Estrogen (E2) and Increased Risk of E2 Plus Progestin (Prog) on Breast Cancer (BrCa). The 2009 Review of the Women's Health Initiative (WHI) Hormone Replacement Therapy (HRT) Published Trials

INTRODUCTION & METHODOLOGY.The objective of this review is to identify from the two WHI published randomized HRT trials the BrCa risk or benefit, with a special focus on different impact of E2-alone vs E2+Prog on human breast carcinogenesis (BrCa-genesis).In the 1st trial (JAMA 2002, 2007), healthy women age 50 - 79 were randomized to E2 plus Prog versus placebo (Plac). Reviewed were Hazard ratios (HRs) for all pts and also for those with or without prior Hormone use. Mean follow up was 5.2 years.In the 2nd trial (JAMA 2004, 2006), women with hysterectomy age 50 - 79 were randomized to E2 alone (without Prog) versus Plac. Mean follow up was 7.1 years. Reviewed were all pts, and also subsets with or without prior E2 or Prog; with or without prior history of Benign Breast Disease (PHBrD); and with or without prior history of a 1st degree relative with BrCa (PH1stRelBrCa).RESULTS.Invasive BrCa incidence:N (%)HR95% C.I.1st TrialAll participants:16,608 (100%)1.260.83 - 1.97No prior Hormone use:12,304 (74.1%)1.060.81 - 1.38Prior Hormone use &lt;5 yrs:3,005 (18.1%)2.131.15 - 3.94*Prior Hormone use 5 - 10 yrs:783 (4.7%)4.611.01 - 21.02*2nd TrialAll participants:10,739 (100%)0.800.62 - 1.04No prior hormone use:5,763 (53.7%)0.650.46 - 0.92*Prior E2 use:4,976 (46.3%)0.980.67 - 1.44Prior E2 + PROG use:468 (4.4%)2.350.60 - 9.14No PHBrD:7,681 (71.5%)0.570.41 - 0.78*No PH1stRelBrCa8,554 (80.0%)0.680.50 - 0.92*CONCLUSION:1. Results from the 1st trial show that concomitant use of E2 with Prog, particularly in women with prior Hormone use, is associated with increased BrCa hazards.2. The results of the 2nd HRT trial indicate that use of HRT with E2 alone is associated with a reduction in BrCa incidence, significant in the majority of women with no prior BrCa risk factors. Also the results show that prior Prog but not prior E2 elevate the risk.3. These data indicate that HRT with E2 alone has a BrCa protective effect, while adding Prog increases the risk.4. These results are also compatible with a dual E2 effect on BrCa-genesis, where exogenous E2 are protective, but endogenous E2 [endE2] are carcinogenic, as shown from decades of anti-end E2 research with Tamoxifen, oophorectomy or Aromatase inhibitors.5. Based on these data we propose that in women with hysterectomy and no prior history of risk factors, the use of HRT with E2 alone as chemoprevention is plausible, and needs urgent verification.* significance, "p" &lt;0.05.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 908.

Childhood, adolescent, and young adult cancer survivors (CAYACS) research program of British Columbia: Data linkage: Results to date

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Background: Long-term survivors of childhood and adolescent cancers are at risk for late mortality and morbidity. Using database linkages we assessed the extent of these issues and health care utilization in a population based cohort in British Columbia. Methods: Retrospective cohorts of 3,483 survivors (>5 years from diagnosis), and representative comparison groups, have been identified from population-based registries. Linkages were made with administrative databases of risk factors and outcomes. Late mortality, second cancers, late morbidity, health services utilization, continuity of care, and educational outcomes, among those diagnosed before age 20 between 1970 to 1995, and followed to 2000, have been examined. Results: Survivors experienced a 9-fold increase in mortality (SMR 9.1, 95% CI 7.8–10.5). Risk of developing a second cancer was 5 times higher than in the general population (SIR 5.0, 95% CI 3.8–6.5). Survivors had three times the odds of being hospitalized (OR 2.97, 95% CI 2.56–3.45) in a three-year period (1998–2000). Survivors were significantly more likely than the population group to consult any physician (excluding oncologists) (adj. RR 1.61, 95% CI 1.51–1.70). Survivors were found to experience a drop in continuity of primary health care as they aged and transitioned into adult care. Survivors were significantly more likely than their peers to receive special education (32.5% vs. 14.1%), most significantly among CNS survivors who received cranial irradiation. Conclusions: Survivors of childhood and adolescent cancers have severe long term health issues and increased health care utilization. Survivors of CNS tumors were at highest risk of poor health and educational outcomes measured. Data linkage provides useful insights for survivorship research.

No significant financial relationships to disclose.

Effect of resynchronization therapy stimulation site on the systolic function of heart failure patients

BACKGROUND

Cardiac resynchronization therapy (CRT) improves systolic function in heart failure patients with ventricular conduction delay by stimulating the left ventricle (LV) or both ventricles (biventricular, BV). Optimal LV site selection is of major clinical interest for CRT device implantation; however, the dependence of hemodynamics on LV stimulation site has not been established. Thus, the objective of this study was to compare the hemodynamic response to CRT for 2 LV coronary vein sites: the free wall and anterior wall. Methods and Results- A total of 30 patients (mean NYHA class, 2.7; mean QRS interval, 152 ms; mean PR interval, 194 ms) enrolled in the PATH-CHF-II trial were studied. CRT was administered with LV and BV stimulation in VDD mode at 4 AV delays. LV stimulation was at the lateral free wall or anterior wall, whereas right ventricular stimulation was fixed near the apex. LV+dP/dt(max) and aortic pulse pressure changes from baseline during CRT were compared for LV sites. Free wall sites with LV and BV stimulation yielded significantly larger LV+dP/dt(max) (14% versus 6%, P<0.001 for LV; 12% versus 5%, P<0.001 for BV) and pulse pressure (8% versus 4%, P<0.001 for LV; 9% versus 5%, P<0.001 for BV) compared with anterior sites. In one third of patients, CRT at free wall sites increased LV+dP/dt(max), whereas it decreased at anterior sites over most AV delays.

CONCLUSION

CRT with LV free wall stimulation produced significantly better LV systolic performance compared with anterior stimulation. Further studies are warranted to prove the clinical superiority of the LV free wall as a site for long-term CRT.

Impact of cardiac resynchronization therapy using hemodynamically optimized pacing on left ventricular remodeling in patients with congestive heart failure and ventricular conduction disturbances

OBJECTIVES

We sought to investigate the impact of six months of cardiac resynchronization therapy (CRT) on echocardiographic variables of left ventricular (LV) function.

BACKGROUND

Cardiac resynchronization therapy has recently been introduced as a new therapeutic modality in patients with advanced heart failure (HF) and conduction abnormalities. However, most studies have only investigated the early hemodynamic effects of CRT.

METHODS

Twenty-five patients (12 women and 13 men; 59.8 +/- 5.1 years old) with advanced HF caused by ischemic (n = 7) or idiopathic dilated cardiomyopathy (n = 18) and a prolonged QRS complex were analyzed. All patients underwent early hemodynamic testing with a randomized testing protocol; echocardiographic measurements were compared before implantation and after six months of CRT.

RESULTS

Left ventricular end-diastolic and end-systolic diameters (LVEDD and LVESD, respectively) were significantly reduced after six months (LVEDD from 71 +/- 10 to 68 +/- 11 mm, p = 0.027; LVESD from 63 +/- 11 to 58 +/- 11 mm, p = 0.007), as were LV end-diastolic and end-systolic volumes (LVEDV from 253 +/- 83 to 227 +/- 112 ml, p = 0.017; LVESV from 202 +/- 79 to 174 +/- 101 ml, p = 0.009). Ejection fraction was significantly increased (from 22 +/- 7% to 26 +/- 9%, p = 0.03). "Nonresponders," with regard to LV volume reduction, had significantly higher baseline LVEDV, compared with "responders" (351 +/- 52 vs. 234 +/- 74 ml, p = 0.018). Overall, there was only mild mitral regurgitation at baseline, with a minor reduction by semiquantitative analysis. The results of early hemodynamic testing did not predict the volume response.

CONCLUSIONS

Cardiac resynchronization therapy may lead to a reduction in LV volumes in patients with advanced HF and conduction disturbances. Volume nonresponders have significantly higher baseline LVEDV.

Cardiac resynchronization for heart failure: present status

Ventricular dysfunction is a hallmark of heart failure, and is often linked to ventricular dilatation and ventricular conduction delays. Recent studies have demonstrated that systolic function can be improved in patients with left bundle branch block by pre-exciting the site of late activation, usually the left ventricular free wall. Furthermore, it has been recently reported that this improvement is associated with a decrease in myocardial oxygen consumption. We hypothesize that the pre-excitation of the region covered by the blocked bundle acts as an "electrical bypass," resynchronizing the contraction of the septum and the left ventricular free wall. In addition, optimization of the electronic atrioventricular delay allows the simultaneous resynchronization of the atrioventricular contractions, and minimization of diastolic mitral regurgitation. Systolic mitral regurgitation may also be reduced by removing the geometric distortion introduced by the left bundle branch block. The recently reported positive outcome of the PATH-CHF I controlled trial reinforces that the positive acute and chronic results that have been reported up to now may translate into long-term clinical benefit for patients with heart failure and conduction defects. Larger studies are needed to confirm these initial results and to establish the impact of this new therapeutic modality on morbidity and mortality. (c)2000 by CHF, Inc.

Cardiac pacing in heart failure patients with left bundle branch block: impact of pacing site for optimizing left ventricular resynchronization

BACKGROUND

Acute left ventricular pacing has been associated with hemodynamic improvement in patients with congestive heart failure and wide QRS complex. We hypothesized that pacing two left ventricular sites simultaneously would produce faster activation and better systolic function than single-site pacing.

METHODS

We selected 14 heart failure patients (NYHA functional class III or IV) in normal sinus rhythm with left bundle branch block and QRS > 150 ms. An 8F dual micromanometer catheter was placed in the aorta for measuring +dP/dt (mmHg/s), aortic pulse pressure (mmHg), and end-diastolic pressure (mmHg). Pacing leads were positioned via coronary veins at the posterior base and lateral wall. Patients were acutely paced VDD at the posterior base, lateral wall, and both sites (dual-site) with 5 atrioventricular delays (from 8 ms to PR -30 ms). Pacing sequences were executed in randomized order using a custom external computer (FlexStim, Guidant CRM).

RESULTS

Dual-site pacing increased peak +dP/dt significantly more than posterior base and lateral wall pacing. Dual-site and posterior base pacing raised aortic pulse pressure significantly more than lateral wall pacing. Dual-site pacing shortened QRS duration by 22 %, whereas posterior base and lateral wall pacing increased it by 2 and 12%, respectively (p = 0.006).

CONCLUSIONS

In heart failure patients with left bundle branch block, dual-site pacing improves systolic function more than single-site stimulation. Improved ventricular activation synchrony, expressed by paced QRS narrowing, may account for the additional benefit of dual- vs single-site pacing in enhancing contractility. This novel approach deserves consideration for future heart failure pacing studies.

Suture closure of femoral arterial puncture sites after coronary angioplasty followed by same-day discharge

BACKGROUND

The purpose of this study was to determine whether immediate suture closure of 8F femoral arterial puncture sites can facilitate same-day discharge after coronary angioplasty.

METHODS AND RESULTS

After coronary angioplasty, 100 patients were randomly assigned to immediate sheath removal with the double-suture Prostar-Plus device or delayed sheath removal with application of a c-clamp. After suture closure, mobilization at 4 hours after sheath removal and discharge 4 hours later were planned. Patients treated with the c-clamp had sheaths removed 4 hours after percutaneous transluminal coronary angioplasty, were mobilized 6 hours later, and discharged the following day. Patients were assessed for groin complications at 8, 24, and 72 hours. Overall, patients who received suture closure were mobilized at 7.1 +/- 5.3 hours and discharged 11. 15 +/- 6.22 hours after sheath removal versus 15.49 +/- 3.9 hours and 21.9 +/- 3.8 hours for patients with the c-clamp (P <.001). Initial failure of the suture device occurred in 5 patients, with 1 requiring surgery for an entrapped device. After the procedure, patients with suture closure more frequently had an ooze of blood (55% vs 24%, P <.001) and a trend to more overt external bleeding (10% vs 2%, P = not significant). Hematomas were reported by 20% of patients in both groups at 72 hours. Overall, patients preferred the suture closure method of sheath removal when assessed by a simple questionnaire. An economic analysis by cost minimization demonstrated potential hospital cost saving.

CONCLUSIONS

Suture closure of 8F arterial puncture sites can facilitate early mobilization and same-day discharge and is considered acceptable by more patients compared with application of the c-clamp. There is potential to realize cost savings with a strategy of same-day discharge.

Effect of pacing chamber and atrioventricular delay on acute systolic function of paced patients with congestive heart failure. The Pacing Therapies for Congestive Heart Failure Study Group. The Guidant Congestive Heart Failure Research Group

BACKGROUND

Previous studies of pacing therapy for dilated congestive heart failure (CHF) have not established the relative importance of pacing site, AV delay, and patient heterogeneity on outcome. These variables were compared by a novel technique that evaluated immediate changes in hemodynamic function during brief periods of atrial-synchronous ventricular pacing.

METHODS AND RESULTS

Twenty-seven CHF patients with severe left ventricular (LV) systolic dysfunction and LV conduction disorder were implanted with endocardial pacing leads in the right atrium and right ventricle (RV) and an epicardial lead on the LV and instrumented with micromanometer catheters in the LV, aorta, and RV. Patients in normal sinus rhythm were stimulated in the RV, LV, or both ventricles simultaneously (BV) at preselected AV delays in a repeating 5-paced/15-nonpaced beat sequence. Maximum LV pressure derivative (LV+dP/dt) and aortic pulse pressure (PP) changed immediately at pacing onset, increasing at a patient-specific optimal AV delay in 20 patients with wide surface QRS (180+/-22 ms) and decreasing at short AV delays in 5 patients with narrower QRS (128+/-12 ms) (P<0.0001). Overall, BV and LV pacing increased LV+dP/dt and PP more than RV pacing (P<0.01), whereas LV pacing increased LV+dP/dt more than BV pacing (P<0.01).

CONCLUSIONS

In this population, CHF patients with sufficiently wide surface QRS benefit from atrial-synchronous ventricular pacing, LV stimulation is required for maximum acute benefit, and the maximum benefit at any site occurs with a patient-specific AV delay.

Transvenous biventricular pacing for heart failure: can the obstacles be overcome?

Despite increasing evidence of hemodynamic benefit and long-term improvement in clinical status of congestive heart failure (CHF) patients with left ventricular and biventricular pacing, the risks and technical limitations of placing a permanent left ventricular pacing lead have prevented widespread clinical adoption of this therapy. Results of this and other recent investigations suggest it is necessary to target specific sites on the left ventricle to maximize hemodynamic benefit. However, limitations and variations of coronary vein anatomy, as well as patient safety, lead dislodgement, pacing thresholds, lead handling, and ease-of-use issues, present technical challenges for current transvenous permanent pacing lead designs. However, a new transvenous lead system based on an over-the-wire design appears to solve many of these problems and has proved feasible in acute clinical studies.

Automatic capture verification by charge-neutral sensing

Automatic capture verification can prolong pulse generator longevity and increase patient safety. However, the detection of evoked response following pacing is complicated due to afterpotentials caused by polarization of electrodes. This study describes a new capture verification scheme, which neutralizes the charges between the pacing electrodes. The hypothesis of the charge-neutral sensing is that the afterpotentials in the ring and the tip are opposite in polarity when pacing in a bipolar mode between ring and tip. Summing the unipolar signals sensed at the tip and the ring should effectively cancel the afterpotentials. This scheme was implemented in an external computer based system and tested during pacemaker implant/replacement on 23 patients during VVI pacing (17 acutely implanted leads and 6 chronic leads). Surface ECG was recorded to provide a marker for capture and noncapture. The pacing voltage was gradually decreased until a noncapture beat was noted. To avoid fusion beats, the pacing rate was programmed approximately 50% higher than the intrinsic rate. The evoked response was high pass filtered and the integral average was calculated for both capture and noncapture beats. The system signal to noise ratio (SNR) was expressed as ratio of the minimum integral average of all capture beats to the maximum integral average of all noncapture beats. The system SNR was 8.6 +/- 1.3 (mean +/- S.E.M; range 1.5-22.8), indicating that the charge-neutral sensing method has, on average, a ninefold safety margin in providing capture verification. Further, evaluation is needed to fully assess this feature in patients with chronic leads.

The optimal pacing rate: an unpredictable parameter

A three phase relation has been demonstrated between increasing heart rate and cardiac output at rest. Phase I with cardiac output increasing with increasing heart rate, phase II a plateau, and phase III decreasing cardiac output with any further increase in heart rate. The "optimal rate" can be defined as the heart rate at the onset of phase II. Twenty patients were studied, 13 male, mean age 60 years (range 31-71 years). All had chronic complete heart block and established DDD pacing. A maximal exercise test was performed to determine peak sinus rate. Exercise hemodynamics were measured using an ambulatory monitor (Capintec Vest), which permits measurement of relative cardiac output and relative ejection fraction. The patients were programmed to VVI pacing at a rate of 60 beats/min and performed three exercise tests at different workloads. The order of workloads was randomized and selected from a range (0, 25, 50, or 75 W) depending on fitness. After 3-minute stabilization, the VVI pacing rate was increased at 1-minute intervals until higher than peak sinus rate giving a total exercise time of 12 minutes. The "optimal rate band" was determined at each workload. The mean of this "optimal rate band" for each workload varied in a nonlinear manner. There was no correlation between "mean optimal rate" and age or the peak rate predicted by the Astrand formula. Current definitions of chronotropic incompetence are inaccurate. Are some of these people at their "optimal rate" already? The arbitrary selection of rate response curves on age related criteria may lead to an impaired hemodynamic response.

A combined analysis of a toothbrush, foam brush, and a chlorhexidine-soaked foam brush in maintaining oral hygiene

Oral hygiene in immunocompromised patients is important in preventing oral infection and may be important in preventing systemic infections. By mechanically reducing bacterial plaque levels in the oral cavity, the risk of infection may be reduced. Foam brushes have been shown to be ineffective in controlling plaque levels and gingivitis. In a 2-week trial, we demonstrated that using a foam brush soaked in chlorhexidine reduces plaque and controls gingivitis as effectively as using a toothbrush. Foam brushes soaked in chlorhexidine should be used when toothbrushing cannot be performed.

Enhancing the effect of oral hygiene with the use of a foam brush with chlorhexidine

The maintenance of oral hygiene for hospitalized patients, particularly medically compromised and immune compromised patients, may reduce the risk of oral and systemic infection. Foam brushes have been recommended for use in these populations, however, the use of a foam brush has not been shown to be an acceptable alternative to the use of a toothbrush. In this study, we demonstrate that the use of a foam brush saturated with chlorhexidine was equally effective in measures of plaque levels and gingivitis as was the use of a toothbrush. Therefore if a toothbrush cannot be used in hospitalized patients, an alternative may be the use of chlorhexidine applied with a foam brush.

Efficacy of chlorhexidine and nystatin rinses in prevention of oral complications in leukemia and bone marrow transplantation

The goal of reducing oral complications during chemotherapy and bone marrow transplantation has received attention at several centers. The current randomized study of 86 adults with leukemia treated with chemotherapy or bone marrow transplantation assessed the potential role of chlorhexidine, nystatin, and saline solution rinses to reduce the findings of oral mucositis, gingivitis, and oral infection. The results of this study did not show a reduction in mucositis with the use of these rinses. However, potential bacterial and fungal pathogens were identified less frequently in the patients using chlorhexidine rinse.

The lack of efficacy of a foam brush in maintaining gingival health: a controlled study

Foam brushes have been used in the oral care of hospitalized patients for many years. However, no controlled study of their efficacy has been conducted. A randomized crossover study, comparing the effectiveness of a foam brush with that of a toothbrush, was carried out. The gingival condition and presence of plaque in the mouths of 29 volunteers were followed. It was shown that a toothbrush was more effective in controlling plaque levels and gingivitis.

Toluidine blue and Lugol's iodine application in the assessment of oral malignant disease and lesions at risk of malignancy

The purpose of the study was to determine if toluidine blue application and counter staining with Logul's iodine would aid in diagnosis of oral dysplastic or malignant lesions. The sensitivity, specificity, and predictive values were studied. Routine use of these tissue stains was found to be sensitive and specific. The use of stains provided better demarcation of oral squamous cell carcinoma and dysplastic changes and assisted in site selection for diagnostic biopsy. The use of toluidine blue and Lugol's iodine can assist in assessment of patients at risk of developing malignant disease and those with lesions that are clinically suspect of dysplasia or malignancy.

The efficacy of chlorhexidine gel in reduction of Streptococcus mutans and Lactobacillus species in patients treated with radiation therapy

Xerostomia may develop in patients with cancer who receive radiotherapy that includes the salivary glands in the field. These patients are at high risk of rampant dental caries. Streptococcus mutans and Lactobacillus species have been associated with dental caries. Quantitative counts of these organisms demonstrated high caries risk due to streptococci in 66% and due to lactobacilli in 100% of patients studied. Use of chlorhexidine rinse was shown to reduce S. mutans counts 1.1 logs and lactobacilli 1.1 logs. The use of chlorhexidine gel resulted in a reduction of S. mutans 1.2 logs and lactobacilli 2.2 logs. In the subjects using the rinse, caries risk due to streptococci was reduced to low levels in 44% and due to lactobacilli in only one subject, with reduction to moderate risk in one third and no change in risk in the remaining patients. The use of chlorhexidine gel was found to reduce the caries risk associated with streptococci to low levels in all patients, and the risk associated with lactobacilli to low and moderate risk in two thirds of patients.

Graves orbitopathy: correlation of CT and clinical findings

The clinical and high-resolution computed tomographic (CT) findings in 71 patients (142 orbits) with Graves orbitopathy and 20 healthy patients (40 orbits) were retrospectively reviewed. The orbits with orbitopathy were subgrouped at clinical examination into those with (n = 18) and those without (n = 124) optic neuropathy. Mean extraocular muscle diameters and the calculated muscle diameter index were significantly increased in all orbits with ophthalmopathy, particularly in those with optic neuropathy. Graves orbitopathy affected the superior muscle group (63.4%) more than the medial (61.3%) or inferior (57%) recti. The most common pattern of muscle involvement involved all five measured extraocular muscles. Solitary muscle involvement most frequently involved the superior muscle group (6.3%). Significant enlargements of the retrobulbar optic nerve sheath and superior ophthalmic vein were noted only in orbits with optic neuropathy. Anterior displacement of the lacrimal gland at CT correlated with clinical palpability and occurred more frequently in patients with optic neuropathy. Severe apical crowding was the most sensitive indication of optic neuropathy at CT.

Clinical study of herpes simplex virus infection in leukemia

Twenty-nine patients with leukemia were observed for the development of and recovery from oral herpes simplex virus (HSV) lesions. In patients with seropositive test results, lymphocyte and monocyte counts may provide a guide to predict the onset of HSV infections and to indicate when to institute acyclovir prophylaxis. When HSV developed, acyclovir was effective in preventing progression of the lesions, which did not resolve until white cell counts had recovered.

Oral Kaposi's sarcoma in acquired immunodeficiency syndrome. Review of management and report of the efficacy of intralesional vinblastine

Treatment of palatal Kaposi's sarcoma (KS) with intralesional injection of vinblastine was seen to provide effective palliation. Of the ten patients studied, four had a 25% to 50% response, two 50% to 75% response, and four had 75% to 100% response with one or two intralesional injections of vinblastine. Response to treatment was followed for a mean of 3.6 months, with recurrence of lesions in two of ten patients.

Biopsychosocial aspects of long-term survival on end-stage renal failure therapy

At ten-years follow-up of 64 haemodialysis patients, 43 had died and 21 were alive, twelve with cadaver renal transplants and nine on haemodialysis. Examination of the influence of psychological, demographic, physical and biochemical factors revealed the Beck Depression Inventory and age as the two most important predictors of survival. The behaviour of the patient was directly responsible for five (11.6%) of the deaths, by suicide in three cases and dietary non-compliance in two cases. Hypothetical mechanisms linking depression with reduced survival have been reviewed. As the impact of depression on survival was maximal in the first few years of dialysis, monitoring for depression should be incorporated into routine care from the start of dialysis together with evaluative interventions that might enhance survival.

Chlorhexidine rinse in prevention of dental caries in patients following radiation therapy

Patients who receive cancer radiotherapy, which compromises salivary gland function, may develop xerostomia. These patients are at increased risk to develop rampant dental caries. Streptococcus mutans and species of lactobacillus have been associated with dental caries. Quantitative counts of these organisms demonstrated high caries risk in 85% of patients studied. The use of chlorhexidine rinse to reduce the counts of S. mutans and lactobacillus was studied. A modest reduction in S. mutans was seen, but little effect was demonstrated on lactobacillus counts. Caries activity was shown to be related to lactobacillus count.

Nuclear DNA, serum sialic acid and measured depth in malignant melanoma for predicting disease recurrence and survival

In a previous multivariate analysis of 151 malignant melanoma patients we identified measured depth of primary lesion (Breslow) and serum N-acetyl-neuraminic acid (NANA) concentration as significant independent predictors of recurrence. Our present study examines the contribution of flow cytometric DNA analysis to prediction of recurrence and survival. Fixed, paraffin-embedded specimens of primary lesions were evaluated from 63 of the previously studied patients. These were prepared for DNA analysis. Of the 28 primaries identified as aneuploid 17 later recurred, while this was true for only 9 of the 35 diploid tumors. On multivariate analysis measured depth was again the most significant predictor of recurrence (p less than 0.001). Additional independent predictors were DNA ploidy (p = 0.02) and NANA (p = 0.05). For survival the independent predictors were measured depth (p = 0.003) and NANA (p = 0.05). Measured depth, DNA ploidy and NANA can be used to construct a model predicting the recurrence risk for stage-I melanoma.

The role of an immunoperoxidase technique in the diagnosis of oral herpes simplex virus infection in patients with leukemia

Laboratory techniques are often used to confirm a clinical diagnosis of oral herpes simplex virus (HSV) infection in patients with leukemia. In the present study, an immunoperoxidase technique (IPT) was used to examine smears taken from the oral mucosa of 44 patients with leukemia at Vancouver General Hospital. It was found that the IPT was as sensitive and specific as viral culture in confirming the presence of HSV. The IPT was found to be more predictive of symptomatic oral HSV disease than viral culture because it did not give positive results if there was only viral shedding in the absence of clinical disease. As the IPT is rapid and inexpensive as well as being specific, sensitive, and predictive, it has a definite role in the laboratory confirmation of oral HSV lesions in leukemics.

Osteonecrosis: study of the relationship of dental extractions in patients receiving radiotherapy

Osteonecrosis is a severe complication of radiotherapy for cancer. Prevention of osteonecrosis is most important, as the condition may be chronic, progressive, and lead to pathologic fracture. The clinical experience, of 627 dental extractions at the Cancer Control Agency of British Columbia either before or after radiotherapy is presented.

Neoadjuvant (preoperative) chemotherapy for breast cancer

Despite recent developments in the treatment of breast cancer, metastatic breast cancer remains an incurable disease. Postoperative adjuvant treatment may improve the survival of a subgroup of node positive, Stage II breast cancer patients, but the proportion of failures is still high. Preoperative adjuvant chemotherapy, an example of a new approach in scheduling of available agents, is based on sound theoretical and experimental principles. In this report, the authors summarize the background data on the rationale for preoperative adjuvant chemotherapy and present preliminary results of this study in which preoperative treatment starting with one course of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) was given to newly diagnosed patients with breast cancer. Analysis of the first 43 patients given such treatment has shown that the side effects were comparable to those seen in patients treated with conventional postoperative chemotherapy, and that the delay time between diagnosis and starting chemotherapy has been substantially reduced compared to the historic group of patients. Additional aspects of this study include the introduction of fine-needle aspiration as the only diagnostic method for obtaining the tissue diagnosis of breast cancer, as well as a more intensive interaction between the surgeons from private practice and the oncology institute.

Ovarian carcinoma: a multivariate analysis of prognostic factors

Five hundred and fifty six women with invasive epithelial ovarian carcinoma were assessed for postoperative treatment between 1966 and 1976. The records of this group were reviewed retrospectively. Sixteen characteristics of the patient and tumor were analyzed for prognostic significance by univariate and multivariate techniques. Tumor grade, the presence of residual disease, and patient performance status are identified as stage-specific independent prognostic factors. These independent factors define patient subsets with good, intermediate, and poor prognosis within each stage. The results show that more effective treatment strategies are required for patients in poor prognosis subsets. Estimates of tumor grade, extent of residual disease, and performance status should be included in reports of treatment outcome.