Highlights of Cardiovascular Disease Prevention Studies Presented at the 2023 American Heart Association Scientific Sessions

PURPOSE OF REVIEW

Focused review highlighting ten select studies presented at the 2023 American Heart Association (AHA) Scientific Sessions.

RECENT FINDINGS

Included studies assessed semaglutide and cardiovascular outcomes in overweight or obese patients without diabetes (SELECT); dapagliflozin in patients with acute myocardial infarction without diabetes (DAPA-MI); effects of dietary sodium on systolic blood pressure in middle-aged individuals (CARDIA-SSBP); long-term blood pressure control after hypertensive pregnancy with physician guided self-management (POP-HT); effect and safety of zilebesiran, an RNA interference therapy, for sustained blood pressure reduction (KARDIA-1); recaticimab add-on therapy in patients with non-familial hypercholesterolemia and mixed hyperlipidemia (REMAIN-2); efficacy and safety of lepodisiran an extended duration short-interfering RNA targeting lipoprotein(a); safety and pharmacodynamic effects of an investigational DNA base editing medicine that inactivates the PCSK9 gene and lowers LDL cholesterol (VERVE-101); automated referral to centralized pharmacy services for evidence-based statin initiation in high-risk patients; and effects of intensive blood pressure lowering in reducing risk of cardiovascular events (ESPRIT). Research presented at the 2023 AHA Scientific Sessions emphasized innovative strategies in cardiovascular disease prevention and management.

Cardiovascular Risk Stratification of Patients Undergoing Hematopoietic Stem Cell Transplantation: The CARE-BMT Risk Score

BACKGROUND

Evidence guiding the pre-hematopoietic stem cell transplantation (HSCT) cardiovascular evaluation is limited. We sought to derive and validate a pre-HSCT score for the cardiovascular risk stratification of HSCT candidates.

METHODS AND RESULTS

We leveraged the CARE-BMT (Cardiovascular Registry in Bone Marrow Transplantation) study, a contemporary multicenter observational study of adult patients who underwent autologous or allogeneic HSCT between 2008 and 2019 (N=2435; mean age at transplant of 55 years; 4.9% Black). We identified the subset of variables most predictive of post-HSCT cardiovascular events, defined as a composite of cardiovascular death, myocardial infarction, heart failure, stroke, atrial fibrillation or flutter, and sustained ventricular tachycardia. We then developed a point-based risk score using the hazard ratios obtained from Cox proportional hazards modeling. The score was externally validated in a separate cohort of 919 HSCT recipients (mean age at transplant 54 years; 20.4% Black). The risk score included age, transplant type, race, coronary artery disease, heart failure, peripheral artery disease, creatinine, triglycerides, and prior anthracycline dose. Risk scores were grouped as low-, intermediate-, and high-risk, with the 5-year cumulative incidence of cardiovascular events being 4.0%, 10.3%, and 22.4%, respectively. The area under the receiver operating curves for predicting cardiovascular events at 100 days, 5 and 10 years post-HSCT were 0.65 (95% CI, 0.59-0.70), 0.73 (95% CI, 0.69-0.76), and 0.76 (95% CI, 0.69-0.81), respectively. The model performed equally well in autologous and allogeneic recipients, as well as in the validation cohort.

CONCLUSIONS

The CARE-BMT risk score is easy to calculate and could help guide referrals of high-risk HSCT recipients to cardiovascular specialists before transplant and guide long-term monitoring.

SuPAR, biomarkers of inflammation, and severe outcomes in patients hospitalized for COVID-19: The International Study of Inflammation in COVID-19

Severe coronavirus disease 2019 (COVID-19) is a hyperinflammatory syndrome. The biomarkers of inflammation best suited to triage patients with COVID-19 are unknown. We conducted a prospective multicenter observational study of adult patients hospitalized specifically for COVID-19 from February 1, 2020 to October 19, 2022. Biomarkers measured included soluble urokinase plasminogen activator receptor (suPAR), C-reactive protein, interleukin-6, procalcitonin, ferritin, and D-dimer. In-hospital outcomes examined include death and the need for mechanical ventilation. Patients admitted in the United States (US, n = 1962) were used to compute area under the curves (AUCs) and identify biomarker cutoffs. The combined European cohorts (n = 1137) were used to validate the biomarker cutoffs. In the US cohort, 356 patients met the composite outcome of death (n = 197) or need for mechanical ventilation (n = 290). SuPAR was the most important predictor of the composite outcome and had the highest AUC (0.712) followed by CRP (0.642), ferritin (0.619), IL-6 (0.614), D-dimer (0.606), and lastly procalcitonin (0.596). Inclusion of other biomarkers did not improve discrimination. A suPAR cutoff of 4.0 ng/mL demonstrated a sensitivity of 95.4% (95% CI: 92.4%-98.0%) and negative predictive value (NPV) of 92.5% (95% CI: 87.5%-96.9%) for the composite outcome. Patients with suPAR < 4.0 ng/mL comprised 10.6% of the cohort and had a 0.8% probability of the composite outcome. Applying this cutoff to the validation cohort yielded a sensitivity of 93.8% (90.4%-96.7%) and NPV of 95.5% (93.1%-97.8%) for the composite outcome. Among commonly measured biomarkers, suPAR offered stronger discriminatory ability and may be useful in triaging low-risk patients with COVID-19.

Cardiovascular Events After Hematopoietic Stem Cell Transplant: Incidence and Risk Factors

Background

Hematopoietic stem cell transplantation (HSCT) is associated with various cardiovascular (CV) complications.

Objectives

We sought to characterize the incidence and risk factors for short-term and long-term CV events in a contemporary cohort of adult HSCT recipients.

Methods

We conducted a multicenter observational study of adult patients who underwent autologous or allogeneic HSCT between 2008 and 2019. Data on demographics, clinical characteristics, conditioning regimen, and CV outcomes were collected through chart review. CV outcomes were a composite of CV death, myocardial infarction, heart failure, atrial fibrillation/flutter, stroke, and sustained ventricular tachycardia and were classified as short-term (≤100 days post-HSCT) or long-term (>100 days post-HSCT).

Results

In 3,354 patients (mean age 55 years; 40.9% female; 30.1% Black) followed for a median time of 2.3 years (Q1-Q3: 1.0-5.4 years), the 100-day and 5-year cumulative incidences of CV events were 4.1% and 13.9%, respectively. Atrial fibrillation/flutter was the most common short- and long-term CV event, with a 100-day incidence of 2.6% and a 5-year incidence of 6.8% followed by heart failure (1.1% at 100 days and 5.4% at 5 years). Allogeneic recipients had a higher incidence of long-term CV events compared to autologous recipients (5-year incidence 16.4% vs 12.1%; P = 0.002). Baseline CV comorbidities were associated with a higher risk of long-term CV events.

Conclusions

The incidence of short-term CV events in HSCT recipients is relatively low. Long-term events were more common among allogeneic recipients and those with pre-existing CV comorbidities.

Highlights of Cardiovascular Disease Prevention Studies Presented at the 2023 European Society of Cardiology Congress

PURPOSE OF REVIEW

To summarize selected late-breaking science on cardiovascular (CV) disease prevention presented at the 2023 European Society of Cardiology (ESC) congress.

RECENT FINDINGS

The NATURE-PARADOX was a naturally randomized trial that used genetic data from the UK Biobank registry to create "cumulative exposure to low-density lipoprotein-cholesterol (LDL-C)" biomarker and evaluate its association with major CV events regardless of plasma LDL-C levels or age. Safety and efficacy data of inclisiran, a PCSK9-interfering mRNA (PCSK9i) administered subcutaneously twice annually, were presented. Data on two new PCSK9is were presented, recaticimab, an oral drug, and lerodalcibep, a subcutaneous drug with a slightly different architecture than currently available PSCK9is. A phase 1 trial on muvalaplin, an oral lipoprotein (a) inhibitor, was presented. An atherosclerotic CV disease (ASCVD) risk prediction algorithm for the Asian population using SCORE2 data was presented. Long-term follow-up of patients enrolled in the CLEAR outcomes trial showed sustained and more significant ASCVD risk reduction with bempedoic acid in high-risk patients. The late-breaking clinical science at the 2023 congress of the ESC extends the known safety and efficacy data of a PCSK9i with the introduction of new drugs in this class. Using cumulative exposure to LDL-C rather than a single value will help clinicians tailor the LDL-C reduction strategy to individual risk and is an important step towards personalized medicine.

Relationship Between Preexisting Cardiovascular Disease and Death and Cardiovascular Outcomes in Critically Ill Patients With COVID-19

BACKGROUND

Preexisting cardiovascular disease (CVD) is perceived as a risk factor for poor outcomes in patients with COVID-19. We sought to determine whether CVD is associated with in-hospital death and cardiovascular events in critically ill patients with COVID-19.

METHODS

This study used data from a multicenter cohort of adults with laboratory-confirmed COVID-19 admitted to intensive care units at 68 centers across the United States from March 1 to July 1, 2020. The primary exposure was CVD, defined as preexisting coronary artery disease, congestive heart failure, or atrial fibrillation/flutter. Myocardial injury on intensive care unit admission defined as a troponin I or T level above the 99th percentile upper reference limit of normal was a secondary exposure. The primary outcome was 28-day in-hospital mortality. Secondary outcomes included cardiovascular events (cardiac arrest, new-onset arrhythmias, new-onset heart failure, myocarditis, pericarditis, or stroke) within 14 days.

RESULTS

Among 5133 patients (3231 male [62.9%]; mean age 61 years [SD, 15]), 1174 (22.9%) had preexisting CVD. A total of 1178 (34.6%) died, and 920 (17.9%) had a cardiovascular event. After adjusting for age, sex, race, body mass index, history of smoking, and comorbidities, preexisting CVD was associated with a 1.15 (95% CI, 0.98-1.34) higher odds of death. No independent association was observed between preexisting CVD and cardiovascular events. Myocardial injury on intensive care unit admission was associated with higher odds of death (adjusted odds ratio, 1.93 [95% CI, 1.61-2.31]) and cardiovascular events (adjusted odds ratio, 1.82 [95% CI, 1.47-2.24]), regardless of the presence of CVD.

CONCLUSIONS

CVD risk factors, rather than CVD itself, were the major contributors to outcomes in critically ill patients with COVID-19. The occurrence of myocardial injury, regardless of CVD, and its association with outcomes suggests it is likely due to multiorgan injury related to acute inflammation rather than exacerbation of preexisting CVD.

REGISTRATION

NCT04343898; https://clinicaltrials.gov/ct2/show/NCT04343898.

Soluble Urokinase Plasminogen Activator Receptor and Venous Thromboembolism in COVID-19

Background Venous thromboembolism (VTE) contributes significantly to COVID-19 morbidity and mortality. The urokinase receptor system is involved in the regulation of coagulation. Levels of soluble urokinase plasminogen activator receptor (suPAR) reflect hyperinflammation and are strongly predictive of outcomes in COVID-19. Whether suPAR levels identify patients with COVID-19 at risk for VTE is unclear. Methods and Results We leveraged a multinational observational study of patients hospitalized for COVID-19 with suPAR and D-dimer levels measured on admission. In 1960 patients (mean age, 58 years; 57% men; 20% Black race), we assessed the association between suPAR and incident VTE (defined as pulmonary embolism or deep vein thrombosis) using logistic regression and Fine-Gray modeling, accounting for the competing risk of death. VTE occurred in 163 (8%) patients and was associated with higher suPAR and D-dimer levels. There was a positive association between suPAR and D-dimer (β=7.34; P=0.002). Adjusted for clinical covariables, including D-dimer, the odds of VTE were 168% higher comparing the third with first suPAR tertiles (adjusted odds ratio, 2.68 [95% CI, 1.51-4.75]; P<0.001). Findings were consistent when stratified by D-dimer levels and in survival analysis accounting for death as a competing risk. On the basis of predicted probabilities from random forest, a decision tree found the combined D-dimer <1 mg/L and suPAR <11 ng/mL cutoffs, identifying 41% of patients with only 3.6% VTE probability. Conclusions Higher suPAR was associated with incident VTE independently of D-dimer in patients hospitalized for COVID-19. Combining suPAR and D-dimer identified patients at low VTE risk. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04818866.

Differences in Inflammation, Treatment, and Outcomes Between Black and Non-Black Patients Hospitalized for COVID-19: A Prospective Cohort Study

PURPOSE

Racial disparities in coronavirus disease 2019 (COVID-19) outcomes have been described. We sought to determine whether differences in inflammatory markers, use of COVID-19 therapies, enrollment in clinical trials, and in-hospital outcomes contribute to racial disparities between Black and non-Black patients hospitalized for COVID-19.

METHODS

We leveraged a prospective cohort study that enrolled 1325 consecutive patients hospitalized for COVID-19, of whom 341 (25.7%) were Black. We measured biomarkers of inflammation and collected data on the use COVID-19-directed therapies, enrollment in COVID-19 clinical trials, mortality, need for renal replacement therapy, and need for mechanical ventilation.

RESULTS

Compared to non-Black patients, Black patients had a higher prevalence of COVID-19 risk factors including obesity, hypertension, and diabetes mellitus and were more likely to require renal replacement therapy (15.8% vs 7.1%, P < .001) and mechanical ventilation (37.2% vs 26.6%, P < .001) during their hospitalization. Mortality was similar between both groups (15.5% for Blacks vs 14.0% for non-Blacks, P = .49). Black patients were less likely to receive corticosteroids (44.9% vs 63.8%, P< .001) or remdesivir (23.8% vs 57.8%, P < .001) and were less likely to be enrolled in COVID-19 clinical trials (15.3% vs 28.2%, P < .001). In adjusted analyses, Black race was associated with lower levels of C-reactive protein and soluble urokinase receptor and higher odds of death, mechanical ventilation, and renal replacement therapy. Differences in outcomes were not significant after adjusting for use of remdesivir and corticosteroids.

CONCLUSIONS

Racial differences in outcomes of patients with COVID-19 may be related to differences in inflammatory response and differential use of therapies.

Inflammation, Hyperglycemia, and Adverse Outcomes in Individuals With Diabetes Mellitus Hospitalized for COVID-19

OBJECTIVE

Diabetes mellitus (DM) is a major risk factor for severe coronavirus disease 2019 (COVID-19) for reasons that are unclear.

RESEARCH DESIGN AND METHODS

We leveraged the International Study of Inflammation in COVID-19 (ISIC), a multicenter observational study of 2,044 patients hospitalized with COVID-19, to characterize the impact of DM on in-hospital outcomes and assess the contribution of inflammation and hyperglycemia to the risk attributed to DM. We measured biomarkers of inflammation collected at hospital admission and collected glucose levels and insulin data throughout hospitalization. The primary outcome was the composite of in-hospital death, need for mechanical ventilation, and need for renal replacement therapy.

RESULTS

Among participants (mean age 60 years, 58.2% males), those with DM (n = 686, 33.5%) had a significantly higher cumulative incidence of the primary outcome (37.8% vs. 28.6%) and higher levels of inflammatory biomarkers than those without DM. Among biomarkers, DM was only associated with higher soluble urokinase plasminogen activator receptor (suPAR) levels in multivariable analysis. Adjusting for suPAR levels abrogated the association between DM and the primary outcome (adjusted odds ratio 1.23 [95% CI 0.78, 1.37]). In mediation analysis, we estimated the proportion of the effect of DM on the primary outcome mediated by suPAR at 84.2%. Hyperglycemia and higher insulin doses were independent predictors of the primary outcome, with effect sizes unaffected by adjusting for suPAR levels.

CONCLUSIONS

Our findings suggest that the association between DM and outcomes in COVID-19 is largely mediated by hyperinflammation as assessed by suPAR levels, while the impact of hyperglycemia is independent of inflammation.

Angiotensin-Converting Enzyme Inhibitors, Angiotensin II Receptor Blockers, and Outcomes in Patients Hospitalized for COVID-19

Background

Use of angiotensin‐converting enzyme inhibitors and angiotensin receptor blockers (ACEi/ARB) is thought to affect COVID‐19 through modulating levels of angiotensin‐converting enzyme 2, the cell entry receptor for SARS‐CoV2. We sought to assess the association between ACEi/ARB, biomarkers of inflammation, and outcomes in patients hospitalized for COVID‐19.

Methods and Results

We leveraged the ISIC (International Study of Inflammation in COVID‐19), identified patients admitted for symptomatic COVID‐19 between February 1, 2020 and June 1, 2021 for COVID‐19, and examined the association between in‐hospital ACEi/ARB use and all‐cause death, need for ventilation, and need for dialysis. We estimated the causal effect of ACEi/ARB on the composite outcomes using marginal structural models accounting for serial blood pressure and serum creatinine measures. Of 2044 patients in ISIC, 1686 patients met inclusion criteria, of whom 398 (23.6%) patients who were previously on ACEi/ARB received at least 1 dose during their hospitalization for COVID‐19. There were 215 deaths, 407 patients requiring mechanical ventilation, and 124 patients who required dialysis during their hospitalization. Prior ACEi/ARB use was associated with lower levels of soluble urokinase plasminogen activator receptor and C‐reactive protein. In multivariable analysis, in‐hospital ACEi/ARB use was associated with a lower risk of the composite outcome of in‐hospital death, mechanical ventilation, or dialysis (adjusted hazard ratio 0.49, 95% CI [0.36–0.65]).

Conclusions

In patients hospitalized for COVID‐19, ACEi/ARB use was associated with lower levels of inflammation and lower risk of in‐hospital outcomes. Clinical trials will define the role of ACEi/ARB in the treatment of COVID‐19.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04818866.

Percutaneous Coronary Intervention in Patients With a History of Gastrointestinal Bleeding (From the Blue Cross Blue Shield of Michigan Cardiovascular Consortium)

Potent antithrombotic agents are routinely prescribed after percutaneous coronary intervention (PCI) to reduce ischemic complications. However, in patients who are at an increased bleeding risk, this may pose significant risks. We sought to evaluate the association between a history of gastrointestinal bleeding (GIB) and outcomes after PCI. We linked clinical registry data from PCIs performed at 48 Michigan hospitals between 1/2013 and 3/2018 to Medicare claims. We used 1:5 propensity score matching to adjust for patient characteristics. In-hospital outcomes included bleeding, transfusion, stroke or death. Post-discharge outcomes included 90-day all-cause readmission and long-term mortality. Of 30,206 patients, 1.1% had a history of GIB. Patients with a history of GIB were more likely to be older, female, and have more cardiovascular comorbidities. After matching, those with a history of GIB (n = 312) had increased post-procedural transfusions (15.7% vs 8.4%; p < 0.001), bleeding (11.9% vs 5.2%; p < 0.001), and major bleeding (2.8% vs 0.6%; p = 0.004). Ninety-day readmission rates were similar among those with and without a history of GIB (34.3% vs 31.3%; p = 0.318). There was no significant difference in post-discharge survival (1 year: 78% vs 80%; p = 0.217; 5 years: 54% vs 51%; p = 0.189). In conclusion, after adjusting for baseline characteristics, patients with a history of GIB had increased risk of post-PCI in-hospital bleeding complications. However, a history of GIB was not significantly associated with 90-day readmission or long-term survival.

In-hospital cardiac arrest in critically ill patients with covid-19: multicenter cohort study

OBJECTIVES

To estimate the incidence, risk factors, and outcomes associated with in-hospital cardiac arrest and cardiopulmonary resuscitation in critically ill adults with coronavirus disease 2019 (covid-19).

DESIGN

Multicenter cohort study.

SETTING

Intensive care units at 68 geographically diverse hospitals across the United States.

PARTICIPANTS

Critically ill adults (age ≥18 years) with laboratory confirmed covid-19.

MAIN OUTCOME MEASURES

In-hospital cardiac arrest within 14 days of admission to an intensive care unit and in-hospital mortality.

RESULTS

Among 5019 critically ill patients with covid-19, 14.0% (701/5019) had in-hospital cardiac arrest, 57.1% (400/701) of whom received cardiopulmonary resuscitation. Patients who had in-hospital cardiac arrest were older (mean age 63 (standard deviation 14) v 60 (15) years), had more comorbidities, and were more likely to be admitted to a hospital with a smaller number of intensive care unit beds compared with those who did not have in-hospital cardiac arrest. Patients who received cardiopulmonary resuscitation were younger than those who did not (mean age 61 (standard deviation 14) v 67 (14) years). The most common rhythms at the time of cardiopulmonary resuscitation were pulseless electrical activity (49.8%, 199/400) and asystole (23.8%, 95/400). 48 of the 400 patients (12.0%) who received cardiopulmonary resuscitation survived to hospital discharge, and only 7.0% (28/400) survived to hospital discharge with normal or mildly impaired neurological status. Survival to hospital discharge differed by age, with 21.2% (11/52) of patients younger than 45 years surviving compared with 2.9% (1/34) of those aged 80 or older.

CONCLUSIONS

Cardiac arrest is common in critically ill patients with covid-19 and is associated with poor survival, particularly among older patients.

Nutrition education and cooking workshops for families of children with cancer: a feasibility study

Background

Changes in food intake are common in children with cancer and are often caused by nausea and perturbations in sense of taste. The VIE (Valorization, Implication, Education) study proposes family-based nutrition and cooking education workshops during childhood cancer treatments. Process evaluation during implementation allows to assess if the intervention was delivered as planned and to determine its barriers and facilitators. The study objective was to describe the implementation process of a nutrition education and cooking workshop program for families of children actively treated for cancer in a non-randomized non-controlled feasibility study.

Methods

Six open-to-all in-hospital workshops were offered on a weekly basis during a one-year implementation phase. We collected qualitative and quantitative data using field notes and activity reports completed by the registered dietician facilitator; surveys and questionnaires fulfilled by the workshop participants and by the families enrolled in the VIE study. Field notes were used to collect only qualitative data. Survey respondents (n = 26) were mostly mothers (n = 19, 73%). Children’s mean age was 7.80 (± 4.99) years and the mean time since diagnosis was 7.98 (± 0.81) months. Qualitative data were codified using hybrid content analysis. The first deductive analysis was based on the Steckler & Linnan concepts. Subthemes were then identified inductively. Quantitative data were presented with descriptive statistics.

Results

Workshop attendance was low (17 participants over 1 year) and 71% of the planned workshops were cancelled due to lack of participants. The principal barriers to participation referred the child’s medical condition, parental presence required at the child’s bedside and challenges related to logistics and time management. The level of interest in the topics addressed was found high or very high for 92% of the participants. The themes that were perceived as the most useful by parents were related to the child’s specific medical condition.

Conclusions

Despite high interest, workshops delivered in a face-to-face format were poorly feasible in our sample population. This supports the need to develop educational programs in pediatric oncology using strategies and delivery formats that address the major barriers for participation encountered by families.

Prostate cancer susceptibility genes: lessons learned and challenges posed

In most developed countries, prostate cancer is the most frequently diagnosed malignancy in men. The extent to which the marked racial/ethnic difference in its incidence rate is attributable to screening methods, environmental, hormonal and/or genetic factors remains unknown. A positive family history is among the strongest epidemiological risk factors for prostate cancer. It is now well recognized that the role of candidate genetic markers to this multifactorial malignancy is more difficult to identify than the identification of other cancer susceptibility genes. Indeed, despite the localization of several susceptibility loci, there has been limited success in identifying high-risk susceptibility genes analogous to BRCA1 or BRCA2 for breast and ovarian cancer. Nonetheless, three strong candidate susceptibility genes have been described, namely ELAC2 (chromosome 17p11/HPC2 region), 2'-5'-oligoadenylate-dependent ribonuclease L (RNASEL), a gene in the HPC1 region, and Macrophage Scavenger Receptor 1 (MSR1), a gene within a region of linkage on chromosome 8p. Additional studies using larger cohorts are needed to fully evaluate the role of these susceptibility genes in prostate cancer risk. It is also of interest to mention that a significant percentage of men with early-onset prostate cancer harbor germline mutation in the BRCA2 gene thus confirming its role as a high-risk prostate cancer susceptibility gene. Although initial segregation analyses supported the hypothesis that a number of rare highly penetrant loci contribute to the Mendelian inheritance of prostate cancer, current experimental evidence better supports the hypothesis that some of the familial risks may be due to inheritance of multiple moderate-risk genetic variants. In this regard, it is not surprising that analyses of genes encoding key proteins involved in androgen biosynthesis and action led to the observation of a significant association between a susceptibility to prostate cancer and common genetic variants in some of those genes.

Influence of Dew Period and Temperature on Foliar Infection of Greenhouse-Grown Tomato by Colletotrichum coccodes

Effects of temperature, duration of leaf wetness, and leaf position on foliar infection of greenhouse-grown tomato (cv. Bonnie Best) by Colletotrichum coccodes were determined by inoculating plants with C. coccodes (5.0 × 10⁵ conidia per ml) and keeping them in a dew chamber for 0, 4, 8, 12, 16, 20, or 24 h of wetting at 15, 20, or 25°C. One week after inoculation, leaf disks were placed on the surface of an amended medium on which colonies of C. coccodes were compact and easily identified, and severity of infection was quantified after 4, 6, and 8 days. There was no infection of plants incubated at 15°C, while plants kept at 20 or 25°C had increasing numbers of colonies when leaf wetness duration was extended beyond 12 and 8 h, respectively. Leaf position had a significant effect, with leaves tending to increase in susceptibility as they age. After 24 h of leaf wetness at 25°C, the mean number of colonies per leaf disk from top, middle, and bottom leaves was 23.8, 29.0, and 34.0, respectively.