RESUMEN

Anomalous coronary artery is a rare but potentially life-threatening alteration in the coronary vascular system that is related to an increased risk of myocardial ischemia, ventricular arrhythmias, heart failure, and sudden cardiac death (SCD). Here, we present the case of a young male who presented to the hospital after a witnessed sudden cardiac arrest. Bystander cardiopulmonary resuscitation was started immediately, and normal sinus rhythm was achieved after electrical cardioversion three times. He was admitted to the ICU for further care upon admission. A CT of the chest showed a potential vascular structure in between the aorta and the pulmonary trunk. He underwent cardiac catheterization, which identified minimal coronary artery disease with the anomalous takeoff of the right coronary artery from the left coronary cusp. A cardiac CT scan obtained also showed an anomalous right coronary artery (ARCA) with an inter-arterial course. After explaining available treatment options and obtaining informed consent, a surgical correction by cardiothoracic surgery was performed using the coronary artery bypass graft technique. The patient recovered well after the surgery and was discharged home. After two years of follow-up, he continued to live life normally without any symptoms. Early and accurate diagnosis of an anomalous coronary artery is imperative for timely intervention, as malignant coronary artery diseases can often have a catastrophic presentation with acute coronary syndromes, myocardial infarction, or SCD. We present here a case of successful diagnosis of ARCA and its prompt surgical correction using coronary artery bypass grafting technique in a young adult. Despite the availability of various other treatment options, our case underscores coronary artery bypass grafting as a viable choice for individuals with anomalous coronary arteries, particularly in urgent situations.

RESUMEN

Aims: Combined mitral valve replacement (MVR) and coronary artery bypass graft (CABG) procedures have been the norm for patients with concomitant mitral valve disease (MVD) and coronary artery disease (CAD) with no large-scale data on their safety and efficacy. Methods and results: The National Inpatient Sample database (2002-18) was queried to identify patients undergoing MVR and CABG. The major adverse cardiovascular events (MACE) and its components were compared using a propensity score-matched (PSM) analysis to calculate adjusted odds ratios (OR). A total of 6 145 694 patients (CABG only 3 971 045, MVR only 1 933 459, MVR + CABG 241 190) were included in crude analysis, while a matched cohort of 724 237 (CABG only 241 436, MVR only 241 611 vs. MVR + CABG 241 190) was selected in PSM analysis. The combined MVR + CABG procedure had significantly higher adjusted odds of MACE [OR 1.13, 95% confidence interval (CI) 1.11-1.14 and OR 1.96, 95% CI 1.93-1.99] and in-hospital mortality (OR 1.29, 95% CI 1.27-1.31 and OR 2.1, 95% CI 2.05-2.14) compared with CABG alone and MVR alone, respectively. Similarly, the risk of post-procedure bleeding, major bleeding, acute kidney injury, cardiogenic shock, sepsis, need for intra-aortic balloon pump, mean length of stay, and total charges per hospitalization were significantly higher for patients undergoing the combined procedure. These findings remained consistent on yearly trend analysis favouring the isolated CABG and MVR groups. Conclusion: Combined procedure (MVR + CABG) in patients with MVD and CAD appears to be associated with worse in-hospital outcomes, increased mortality, and higher resource utilization compared with isolated CABG and MVR procedures. Randomized controlled trials are needed to determine the relative safety of these procedures in the full spectrum of baseline valvular and angiographic characteristics.

RESUMEN

BACKGROUND: The Penumbra Indigo aspiration system (Penumbra Inc., Alameda, CA, USA) is a suction embolectomy device that was cleared by the Food and Drug Administration for use in acute pulmonary embolism (PE). While this device has proven to be safe in clinical trials, real-world data are minimal. METHODS: The "Manufacturer and User Facility Device Experience" MAUDE database was queried for reports of Penumbra indigo system from January 2020 to August 2021. RESULTS: A total of 2118 reports were found during the study period. After the exclusion of duplicate and incomplete reports as well as reports not related to PE, our final cohort included 67 reports related to Penumbra indigo device failure. The most common failure mode was Lightning unit malfunction (35.8%, n = 24) followed by rotating hemostasis valve malfunction (31.3%, n = 21). Three (4.5%) patients died; two (3%) from fatal pulmonary vessel perforation, and one from fatal right-sided heart failure. There was one case (1.5%) of pericardial effusion, while there were no cases of hemoptysis or blood transfusion. CONCLUSION: The overall number of reports in the MAUDE registry related to the Penumbra Indigo aspiration system is small (67 reports in 20 months). The most common reported failure mode was Lightning unit malfunction. These data serve to inform operators about potential issues when using the Penumbra Indigo thrombus aspiration system and identify areas on which to focus further device iteration.

Asunto(s)

RESUMEN

INTRODUCTION: The comparative efficacy and safety of valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) and redo-surgical AVR (redo-SAVR) in patients with degenerated bioprosthetic aortic valves remain unknown. METHOD: Digital databases were searched to identify relevant articles. Unadjusted odds ratios for dichotomous outcomes were calculated using a random effect model. A total of 11 studies comprising 8326 patients (ViV-TAVR = 4083 and redo-SAVR = 4243) were included. RESULTS: The mean age of patients undergoing ViV-TAVR was older, 76 years compared to 73 years for those undergoing SAVR. The baseline characteristics for patients in ViV-TAVR vs. redo-SAVR groups were comparable. At 30-days, the odds of all-cause mortality (OR 0.45, 95% CI 0.30-0.68, p = .0002), cardiovascular mortality (OR 0.44, 95% CI 0.26-0.73, p = .001) and major bleeding (OR 0.29, 95% CI 0.15-0.54, p = .0001) were significantly lower in patients undergoing ViV-TAVR compared to redo-SAVR. There were no significant differences in the odds of cerebrovascular accidents (OR 0.91, 95% CI 0.52-1.58, p = .74), myocardial infarction (OR 0.92, 95% CI 0.44-1.92, p = .83) and permanent pacemaker implantation (PPM) (OR 0.54, 95% CI 0.27-1.07, p = .08) between the two groups. During mid to long-term follow up (6-months to 5-years), there were no significant differences between ViV-TAVR and redo-SAVR for all-cause mortality, cardiovascular mortality and stroke. ViV-TAVR was, however, associated with higher risk of prosthesis-patient mismatch and greater transvalvular pressure gradient post-implantation. CONCLUSION: ViV-TAVR compared to redo-SAVR appears to be associated with significant improvement in short term mortality and major bleeding. For mid to long-term follow up, the outcomes were similar for both groups.

Asunto(s)

RESUMEN

BACKGROUND: The objective was to assess current training preferences, expertise, and comfort with transfemoral access (TFA) and transradial access (TRA) amongst cardiovascular training fellows and teaching faculty in the United States. As TRA continues to dominate the field of interventional cardiology, there is a concern that trainees may become less proficient with the femoral approach. METHODS: A detailed questionnaire was sent out to academic General Cardiovascular and Interventional Cardiology training programs in the United States. Responses were sought from fellows-in-training and faculty regarding preferences and practice of TFA and TRA. Answers were analyzed for significant differences between trainees and trainers. RESULTS: A total of 125 respondents (75 fellows-in-training and 50 faculty) completed and returned the survey. The average grade of comfort for TFA, on a scale of 0 to 10 (10 being most comfortable), was reported to be 6 by fellows-in-training and 10 by teaching faculty (p < 0.001). TRA was the first preference in 95% of the fellows-in-training compared to 69% of teaching faculty (p 0.001). While 62% of fellows believed that they would receive the same level of training as their trainers by the time they graduate, only 35% of their trainers believed so (p 0.004). CONCLUSION: The shift from TFA to radial first has resulted in significant concern among cardiovascular fellows-in training and the faculty regarding training in TFA. Cardiovascular training programs must be cognizant of this issue and should devise methods to assure optimal training of fellows in gaining TFA and managing femoral access-related complications.

Asunto(s)

RESUMEN

This survey-based analysis aims to highlight key limitations to a wider adoption of coronary artery calcium (CAC) scoring as a means of screening asymptomatic individuals for atherosclerotic cardiovascular disease. The need for a screening tool that adds objective anatomical information to historically established risk scores in the aforementioned population has been met by this imaging modality. Despite that, there has been a hesitance towards frequent usage of these scans. Within the pre-set sampling frame of the University of Toledo, a convenience sampling technique was used to reach out to 60 health care providers. The resultant responses were analyzed and discussed. In addition to identifying patients who need to be worked up further, CAC scans can also help re-stratify patients within-risk groups and inform decision-making regarding the use of lipid-lowering therapies. The public health impact of a greater but appropriate utilization of this diagnostic tool will be impactful. This analysis seeks to better understand real-life obstacles to a wider adoption of these scans and attempts to lay out policy recommendations to address these issues.

RESUMEN

BACKGROUND: Radial access for lower-extremity peripheral vascular interventions (PVIs) has been limited due to inadequate equipment lengths. The Terumo R2P Destination Slender sheath is a relatively new sheath designed for these interventions. However, complications related to this sheath or access strategy for lower-extremity PVI have not been reported. CASE SUMMARY: A 69-year-old woman presented with purple discolouration of her 1st and 5th toes of the left foot for approximately 1 month. Lower-extremity arterial duplex ultrasound showed mid left superficial femoral artery (SFA) greater than 90% stenosis. Peripheral angiogram was performed via the left radial artery and this confirmed the presence of severe left SFA stenosis. Intra-arterial vasodilators including verapamil and nitroglycerine were administered to prevent radial artery spasm. Next, we attempted to deliver the Terumo 6-Fr R2P Destination Slender 119 cm sheath for the interventional procedure. However, the sheath became stuck at the level of mid axillary artery due to severe radial artery spasm. Despite use of intra-arterial vasodilators, deep sedation with propofol, and gentle retraction, the sheath could not be removed and eventually broke requiring surgical removal. DISCUSSION: This case demonstrates severe radial artery spasm causing sheath entrapment that required emergency surgery for sheath removal. Unfortunately, the sheath could not be removed despite typical manoeuvres for severe spasm including intra-arterial vasodilators and deep sedation with propofol. Physicians performing PVIs via radial access need to be aware of this potentially serious complication.

RESUMEN

OBJECTIVES: Endovascular therapy (EVT) has emerged as an alternative to surgery for the treatment of symptomatic infrarenal aortic stenosis (IAS). However, long-term outcomes with EVT are unknown. METHODS: We performed a retrospective review of patients with IAS treated with the endovascular approach at the University of Toledo Medical Center, Toledo, Ohio. We compared our single-center study (SCS) with a review of published studies (ROS) regarding complications, patency rate (PR), and repeat intervention rate (RIR). Pearson's Chi-square or Fisher's exact test, and the Student's t-test or Mann-Whitney U-test, were used for categorical and continuous variables, respectively. For the ROS data, we used a pooled mean of means. RESULTS: A total of 25 patients from the SCS were compared with 698 patients from the ROS data. Mean age was 63 years vs 58 years, females comprised 48% vs 54%, Rutherford class 3 comprised 68% vs 69%, and mean follow-up duration was 67 months vs 44 months in SCS vs ROS, respectively. PR at 12 months was 96% vs 90%, while PR at maximum time-period was 92% vs 76% in SCS vs ROS, respectively. RIR in SCS was 4% at 12 months and 8% at the maximum time period (20.2 years). RIR in ROS was 24% at the maximum time period (10 years). The mortality rate was 0% in the SCS arm vs 3.4% in the ROS arm. CONCLUSION: EVT is highly effective and safe, and was associated with excellent patency rates at long-term follow-up.

Asunto(s)

RESUMEN

Anomalous origin of right coronary artery with interarterial course (ARCA-IA) is a risk factor for sudden death and other cardiac complications. Surgical correction remains its gold standard treatment. We describe clinical characteristics, workup, surgical techniques and outcomes of ARCA-IA at our center. A retrospective analysis of cardiovascular database was performed. From March 2005 through January 2011, 11 patients with mean age of 53 ± 18 years were diagnosed with ARCA-IA. Reported symptoms included chest pain (64%), arrhythmia [27%; i.e. atrial flutter (9%), recurrent supraventricular tachycardia (9%), ventricular tachycardia (9%)], syncope (18%), dyspnea (9%) and aborted sudden cardiac death (9%). Chest pain (n = 7) was episodic and lasted longer than 6 months before diagnosis. Initial diagnosis was made at coronary computed tomography in two patients and at cardiac catheterization in nine patients. Four patients had positive stress test and were subsequently found to have ARCA-IA at cardiac catheterization. There was no operative mortality. Surgery (bypass with ligation of native vessel or translocation and reimplantation) was performed in seven patients. Three patients refused surgery, and in one patient, surgery was not considered due to comorbidities. Symptom relief was noted in all surgical patients. At mean follow-up of 36 months, two patients had noncardiac-related deaths whereas nine were asymptomatic. There were no deaths reported in patients treated surgically. Definitive surgery is indicated in symptomatic ARCA-IA and is associated with excellent long-term outcome. RCA dominance in ARCA-IA is an adverse marker with increased symptoms; this hypothesis should be tested in larger studies.

Asunto(s)

RESUMEN

BACKGROUND: Incidence and outcomes of acute coronary syndrome (ACS) immediately following transcatheter aortic valve replacement (TAVR) remain largely unknown. OBJECTIVES: This study sought to assess the incidence, clinical characteristics, and outcomes of ACS following TAVR. METHODS: We queried the National Readmission Database from January 2012 to September 2015 for TAVR admissions with and without ACS, creating a propensity-matched cohort to compare outcomes. RESULTS: A total of 48,454 patients underwent TAVR, with 1,332 (2.75%) developing ACS. TAVR patients with ACS compared to those without ACS had a significantly higher incidence of acute kidney injury (24.7 vs. 19.2%; p = .001), ischemic stroke (3.7 vs. 2.3%; p = .04), vascular complications (8.6 vs. 5.8%; p = .008), cardiogenic shock (9.8 vs. 1.9%; p < .001), cardiac arrest (5.1 vs. 2.8%; p = .002), mechanical circulatory support (8.1 vs. 1.5%; p < .001), and in-hospital mortality (9.6 vs. 3.4%; p < .001). Additionally, TAVR with ACS had longer lengths of stay (median 10 days vs. 6 days; p < .001) and hospital charges (median $23,200 vs. $19,000; p < .001). Positive predictors of ACS were history of PCI (odds ratio, 1.43; 95% CI: 1.25-1.63), hyperlipidemia (odds ratio, 1.20; 95% CI: 1.07-1.34), chronic blood loss anemia (odds ratio, 2.16; 95% CI: 1.54-3.03), chronic kidney disease (odds ratio, 1.17; 95% CI: 1.04-1.31), fluid and electrolyte disorders (odds ratio, 1.65; 95% CI: 1.47-1.85), and weight loss (odds ratio, 1.53; 95% CI: 1.22-1.91). Heart failure (34%) was the most common reason for readmission in the ACS cohort. CONCLUSION: ACS after TAVR is uncommon but is associated with worse clinical outcomes and increased healthcare resource utilization.

Asunto(s)

Asunto(s)

RESUMEN

INTRODUCTION: Common femoral endarterectomy (CFE) has been the therapy of choice for common femoral artery atherosclerotic disease (CFA-ASD). In the past, there was inhibition to treat CFA-ASD endovascularly with stents due to fear of stent fracture and compromise of future vascular access site. However, recent advances and new evidence suggest that CFA may no longer be a 'stent-forbidden zone'. In the light of new evidence, we conducted a meta-analysis to determine the use of endovascular treatment for CFA-ASD and compare it with common femoral endarterectomy in the present era. METHODS: Using certain MeSH terms we searched multiple databases for studies done on endovascular and surgical treatment of CFA-ASD in the last two decades. Inclusion criteria were randomized control trials, observational, prospective, or retrospective studies evaluating an endovascular treatment or CFE for CFA-ASD. For comparison, studies were grouped based on the treatment strategy used for CFA-ASD: endovascular treatment with selective stenting (EVT-SS), endovascular treatment with routine stenting (EVT-RS), or common femoral endarterectomy (CFE). Primary patency (PP), target lesion revascularization (TLR), and complications were the outcomes studied. We did proportional meta-analysis using a random-effect model due to heterogeneity among the included studies. If confidence intervals of two results do not overlap, then statistical significance is determined. RESULTS: Twenty-eight studies met inclusion criteria (7 for EVT-RS, 8 for EVT-SS, and 13 for CFE). Total limbs involved were 2914 (306 in EVT-RS, 678 in EVT-SS, and 1930 in CFE). The pooled PP at 1 year was 84% (95% CI 75-92%) for EVT-RS, 78% (95% CI 69-85%) for EVT-SS, and 93% (95% CI 90-96%) for CFE. PP at maximum follow-up in EVT-RS was 83.7% (95% CI 74-91%) and in CFE group was 88.3% (95% CI 81-94%). The pooled target lesion revascularization (TLR) rate at one year was 8% (95% CI 4-13%) for EVT-RS, 19% (95% CI 14-23%) for EVT-SS, and 4.5% (95% CI 1-9%) for CFE. The pooled rate of local complications for EVT-RS was 5% (95% CI 2-10%), for EVT-SS was 7% (95% CI 3 to 12%), and CFE was 22% (95% CI 14-32%). Mortality at maximum follow-up in CFE group was 23.1% (95% CI 14-33%) and EVT-RS was 5.3% (95% CI 1-11%). CONCLUSION: EVT-RS has comparable one-year PP and TLR as CFE. CFE showed an advantage over EVT-SS for one-year PP. The complication rate is lower in EVT RS and EVT SS compared to CFE. At maximum follow-up, CFE and EVT-RS have similar PP but CFE has a higher mortality. These findings support EVT-RS as a management alternative for CFA-ASD.

Asunto(s)

RESUMEN

Introduction Wearable cardioverter defibrillators (WCD) are recommended for patients with a high risk of sudden cardiac death (SCD) secondary to arrhythmia that have not qualified for placement of an implantable cardiac defibrillator (ICD). This study provides insights into a single-center experience with WCD in terms of its usage and safety. Materials and methods We studied all patients that were prescribed a WCD in the Fairview Hospital in Cleveland Clinic Health System, from January 2014 to June 2016. Institutional Review Board of the Cleveland Clinic approved the study. A retrospective chart review was performed to collect data regarding demographics and baseline comorbidities including age, gender, history of hypertension, diabetes, coronary artery disease, and chronic kidney disease. The patients that were lost to follow up in our electronic medical record (EMR) were excluded. Ejection fraction (EF) at the time of diagnosis and follow-up was recorded. The primary outcome was ICD placement at follow up focusing on appropriate use while the secondary outcome was delivery of shock (appropriate or inappropriate) focusing on efficacy and safety of the device. Patients were stratified based on ICD placement. Statistical Package for the Social Sciences (SPSS), version 23 (IBM Corp., NY, USA) was used for the statistical analysis. Results We identified 73 patients with WCD placement. After the exclusion of 23/73 (31.5%) patients due to loss of follow-up, 50 patients were included in the study (n=50). Clinical characteristics showed 66% patients were males, 76% had hypertension, 40% had diabetes, 34% had chronic kidney disease, 56% patient had a New York Heart Association functional status of >II and 34% were on anti-arrhythmic medication. Indication for WCD use was ischemic cardiomyopathy in 23/50 (46%) patients and non-ischemic cardiomyopathy in 27/50 (54%) patients. No ICD was placed in 39/50 (78%) patients and ICD was placed in 11/50 (22%) patients at end time of follow up. Mean age was 59.9 years (95% confidence interval (CI), 55.9 - 63.9 years) in the group with no ICD placement and 63.5 years (95% CI, 56.5 - 70.6 years) in the group with ICD placement. Mean EF in the group with no ICD placement at the time of diagnosis was 25.8% (95% CI, 23.8% - 27.9%) which improved by 18.8% to a mean EF of 44.6% (41.1% - 48.1%) at the follow-up. Mean EF in the group with ICD placement was 32.7% (95% CI, 27.6% - 37.9%) which reduced by 4.1% to mean EF of 28.6% (95% CI, 12.2% - 44.9%) which was statistically significant (p<0.0001). Patients who had no ICD placement were followed for an average of 162 days and with ICD placement for 78 days. There was no difference between ischemic or nonischemic groups in getting the ICD. There were no shocks delivered whether appropriate or inappropriate in our population. Conclusion Almost a quarter of the patients that were prescribed WCD in our center ended up with an implanted device which demonstrates appropriate use. Equally important was the observed safety of WCDs as a treatment modality with no inappropriate shocks recorded in the followed cohort.

RESUMEN

Transcatheter aortic valve implantation (TAVI) is recommended for inoperable and high risk surgical patients with severe aortic stenosis. It is noninferior to surgical aortic valve replacement (SAVR) in intermediate risk candidates. TAVI is currently being assessed for low surgical risk individuals. We performed a meta-analysis of randomized controlled trials (RCTs) and matched observational studies between TAVI and SAVR in low surgical risk patients. The primary outcomes were short-term and mid-term mortality and neurologic events. Secondary outcomes were other periprocedure complications. A total of 8 studies (3 RCTs and 5 matched observational studies) totaling 6,686 patients were included. No difference was seen in short-term mortality and neurologic events (risk ratio [RR] 0.68, 95% confidence interval [CI] 0.45 to 1.03, p 0.07 and RR 0.76, 95% CI 0.52 to 1.13, p 0.18) as well as mid-term mortality and neurologic events (RR 0.89, 95% CI 0.54 to 1.47, p 0.65 and RR 1.04, 95% CI 0.55 to 1.97, p 0.9) between the 2 groups. Reduced risk of new onset atrial fibrillation (RR 0.14, 95% CI 0.08 to 0.25, p <0.00001), acute kidney injury (RR 0.43, 95 CI 0.23 to 0.82, p 0.01), and bleeding (RR 0.43, 95% CI 0.27 to 0.69, p 0.0005) whereas increased risk of ≥ moderate aortic regurgitation (RR 6.53, 95% CI 3.48 to 12.24, p <0.00001), pacemaker or defibrillator implantation (RR 3.11, 95% CI 1.96 to 4.94, p <0.00001) and vascular complications (RR 5.29, 95% CI 1.58 to 17.70, p 0.007) was noted in TAVI arm. In conclusion, TAVI is comparable to SAVR in terms of short-term and mid-term mortality and neurologic events in low surgical risk patients. The risk of periprocedure events is variable.

Asunto(s)

RESUMEN

Infective endocarditis is typically caused by Staphylococcus aureus (S. aureus), coagulase-negative staphylococci and streptococci but infection with Corynebacterium striatum (C. striatum) is also becoming prominent. We present the case of a 65-year-old female with a recent history of the coronary artery bypass graft with bioprosthetic aortic valve replacement. The surgery was complicated by sternal wound dehiscence with methicillin-sensitive S. aureus (MSSA) for which she was treated for six weeks with intravenous antibiotics. Two months later, she was found to have C. striatum which was treated. A transesophageal echocardiogram was done as well which did not show any vegetation. She presented to the hospital with vomiting, cough, fever, and shortness of breath. She had pyuria on urinalysis and was started on empiric antibiotics after taking blood cultures. She decompensated soon after admission and was transferred to the intensive care unit where she had a pulseless ventricular tachycardia and was resuscitated but required vasopressor support. The blood cultures from admission started growing C. striatum again. Daptomycin was added to the empiric antibiotics and supportive care was continued, but the family decided to make her 'do not resuscitate - comfort care only'. The support was withdrawn and she passed away.

RESUMEN

PURPOSE OF REVIEW: Congestive heart failure (CHF) is a major cause of morbidity, mortality, and health care expenditure. Although the role of renal artery stenosis (RAS) in CHF has been known, there are a number of areas of uncertainty. RECENT FINDINGS: The prevalence of RAS in subjects with CHF varies from 15 to 54% depending on the cohort studied and the diagnostic modality used to identify RAS. In subjects with CHF, the presence of RAS is associated with worse renal function and a higher risk for mortality during long-term follow-up. There are many unanswered questions regarding the role of RAS in subjects with CHF. This review highlights those questions and helps to set the research agenda in this area.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Iatrogenic coronary artery dissection is a potentially life-threatening complication of cardiovascular interventions. The optimal management of iatrogenic coronary artery dissection is not clear; however, both conservative management and percutaneous or surgical revascularization have been performed depending on the patient's clinical status and the extent of dissection. We present the first reported case of right coronary artery dissection after Bentall procedure performed for ascending aortic aneurysm. Urgent percutaneous intervention using adjunctive coronary imaging was performed with excellent clinical recovery. In this article, we highlight coronary artery dissection after Bentall procedure as a possible complication, provide an insight into various options in its management, and review published data on iatrogenic coronary artery dissection. We also discuss the challenges in percutaneous treatment of coronary artery dissection with special focus on intracoronary imaging for accurate diagnosis and guidance in the management of this complex lesion.