Prospects for percutaneous valve therapies

Two Cases of Surgical Correction of Recurrent Mitral Regurgitation due to Failed Catheter- Delivered Mitral Clip (MitraClip)

From April 2018 to February 2021, 150 patients underwent MitraClip implantation for severe functional mitral regurgitation (MR) at our hospital. Two of our patients, an 85-year-old man and an 84-year-old woman, developed a single leaflet device attachment in the acute phase after the implantation and had severe residual MR requiring surgical correction. The recurrent MR was first pointed out on day 5 and day 4, and the duration between MitraClip implantation and surgery was 13 and 55 days, respectively. Due to strong adhesions with the clips and severe valve damage after MitraClip implantation, both cases underwent mitral valve replacement with a good postoperative course. In patients with a high-risk baseline profile, surgical mitral valve replacement after failed MitraClip implantation should be considered at an optimal timing, and a detailed echocardiographic follow-up is required.

A biomimetic multilayered polymeric material designed for heart valve repair and replacement

Materials currently used to repair or replace a heart valve are not durable. Their limited durability related to structural degeneration or thrombus formation is attributed to their inadequate mechanical properties and biocompatibility profiles. Our hypothesis is that a biostable material that mimics the structure, mechanical and biological properties of native tissue will improve the durability of these leaflets substitutes and in fine improve the patient outcome. Here, we report the development, optimization, and testing of a biomimetic, multilayered material (BMM), designed to replicate the native valve leaflets. Polycarbonate urethane and polycaprolactone have been processed as film, foam, and aligned fibers to replicate the leaflet's architecture and anisotropy, through solution casting, lyophilization, and electrospinning. Compared to the commercialized materials, our BMMs exhibited an anisotropic behavior and a closer mechanical performance to the aortic leaflets. The material exhibited superior biostability in an accelerated oxidization environment. It also displayed better resistance to protein adsorption and calcification in vitro and in vivo. These results will pave the way for a new class of advanced synthetic material with long-term durability for surgical valve repair or replacement.

Comparison of different transcatheter interventions for treatment of mitral regurgitation: A protocol for a network meta-analysis

BACKGROUND

The arrival of transcatheter mitral valve therapies has provided feasible and safe alternatives to medical and surgical treatments for mitral regurgitation. The aim of this study is to estimate the relative efficacy and safety of different transcatheter mitral valve therapies for mitral regurgitation patients through network meta-analysis.

METHODS

A systematic search will be performed using PubMed, EMBASE, the Cochrane Library, Web of Science, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure to include random controlled trials and nonrandom controlled trials comparing the efficacy and safety of different transcatheter mitral valve techniques. The risk of bias for the included nonrandom controlled studies will be evaluated according to Risk of Bias in Non-randomized Studies - of Interventions. For random controlled trials, we will use Cochrane Handbook version 5.1.0 as the risk of bias tool. A Bayesian network meta-analysis will be conducted using R-4.0.3 software. Grading of recommendations assessment, development, and evaluation will be used to assess the quality of evidence.

RESULTS

The results of this network meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This study will provide broad evidence of efficacy and safety of different transcatheter mitral valve therapies for treatment of mitral regurgitation and provide suggestions for clinical practice and future research.

PROTOCOL REGISTRATION NUMBER

INPLASY2020110034.

Aortic valve bypass surgery in severe aortic valve stenosis: Insights from cardiac and brain magnetic resonance imaging

OBJECTIVE

To investigate and describe the distribution of aortic and cerebral blood flow (CBF) in patients with severe valvular aortic stenosis (AS) before and after aortic valve bypass (AVB) surgery.

METHODS

We enrolled 10 consecutive patients who underwent AVB surgery for severe AS. Cardiovascular magnetic resonance imaging (CMR) and brain magnetic resonance imaging were performed as baseline before surgery and twice after surgery. Quantitative flow measurements were obtained using 1.5-T magnetic resonance imaging (MRI) scanner phase-contrast images of the ascending aorta, descending thoracic aorta (3 cm proximally and distally from the conduit-to-aorta anastomosis), and ventricular outflow portion of the conduit. The evaluation of CBF was performed using 3.0-T MRI scanner arterial spin labeling (ASL) through sequences acquired at the gray matter, dorsal default-mode network, and sensorimotor levels.

RESULTS

Conduit flow, expressed as the percentage of total antegrade flow through the conduit, was 63.5 ± 8% and 67.8 ± 7% on early and mid-term postoperative CMR, respectively (P < .05). Retrograde perfusion from the level of the conduit insertion in the descending thoracic aorta toward the aortic arch accounted for 6.9% of total cardiac output and 11% of total conduit flow. We did not observe any significant reduction in left ventricular stroke volume at postoperative evaluation compared with preoperative evaluation (P = .435). No differences were observed between preoperative and postoperative CBF at the gray matter, dorsal default-mode network, and sensorimotor levels (P = .394).

CONCLUSIONS

After AVB surgery in patients with severe AS, cardiac output is split between the native left ventricular outflow tract and the apico-aortic bypass, with two-thirds of the total antegrade flow passing through the latter and one-third passing through the former. In our experience, CBF assessment confirms that the flow redistribution does not jeopardize cerebral blood supply.

Mitral Valve Surgery: Current Minimally Invasive and Transcatheter Options

The mitral valve is a highly complex structure, the competency and function of which relies on the harmonious action of its component parts. Minimally invasive cardiac surgery (MICS) for mitral valve repair or replacement (MVR/r) has been performed successfully with incremental improvements in techniques over the past decade. These minimally invasive procedures, while attractive to patients and referring physicians, should meet the same high bar for optimal clinical outcomes and long-term durability of valve repair as traditional sternotomy procedures. The majority of MICS MVR/r procedures are performed via a right minithoracotomy approach with direct or camera-assisted visualization, with a minority of centers performing robotic MVR/r. Outcomes with MICS MVR/r have been shown to have similar morbidity and mortality rates as traditional sternotomy MV procedures but with the advantage of reduced transfusions, postoperative atrial fibrillation, and time to recovery. More recently, transcatheter mitral valve repair and replacement (TMVR/r) has become a reality. Percutaneous MV repair technology is currently FDA approved for patients with nonsurgical high-risk degenerative mitral regurgitation. Other TMVR/r technology is at various levels of preclinical and clinical investigation, although these devices are proving to be more challenging compared to transcatheter aortic valve replacement (TAVR) due to the significantly more complex mitral anatomy and the greater heterogeneity of mitral disease requiring treatment. In this article, we review current techniques for MICS MVR/r and upcoming catheter-based therapies for the mitral valve.

Development of a postgraduate interventional cardiac nursing curriculum

Interventional cardiology practices have advanced immensely in the last two decades, but the educational preparation of the workforce in cardiac catheter laboratories has not seen commensurate changes. Although on-the-job training has sufficed in the past, recognition of this workforce as a specialty practice domain now demands specialist educational preparation. The aim of this paper is to present the development of an interventional cardiac nursing curriculum nested within a Master of Nursing Practice in Australia. International and national health educational principles, teaching and learning theories and professional frameworks and philosophies are foundational to the program designed for interventional cardiac specialist nurses. These broader health, educational and professional underpinnings will be described to illustrate their application to the program's theoretical and clinical components. Situating interventional cardiac nursing within a Master's degree program at University provides nurses with the opportunities to develop high level critical thinking and problem solving knowledge and skills.

Radiology of cardiac devices and their complications

This article familiarizes the reader with several different cardiac devices including pacemakers and implantable cardioverter defibrillators, intra-aortic balloon pumps, ventricular assist devices, valve replacements and repairs, shunt-occluding devices and passive constraint devices. Many cardiac devices are routinely encountered in clinical practice. Other devices are in the early stages of development, but circumstances suggest that they too will become commonly found. The radiologist must be familiar with these devices and their complications.

Current and new-generation transcatheter aortic valve devices: an update on emerging technologies

Transcatheter aortic valve implantation (TAVI) has become an accepted treatment option for patients with symptomatic severe aortic stenosis who are at high risk for traditional surgical aortic valve replacement. In particular, TAVI has been shown to reduce mortality in a randomized comparison with medical treatment and to be non-inferior to surgical aortic valve replacement in 'high-risk operable' patients. From its early stages it became apparent that TAVI has tremendous potential and thus considerable efforts were made to design new devices and advance valve technology in order to improve outcomes and increase TAVI applications in complex anatomies and in patients with multiple co-morbidities. In this review, we present the advances in transcatheter aortic valve technology and discuss the current evidence on the new-generation TAVI devices.

Catheter interventions in congenital heart disease without regular catheterization laboratory equipment: the chain of hope experience in Rwanda

This report describes the feasibility and safety of cardiac catheterization in a developing country without access to a regular cardiac catheterization laboratory. The equipment used for imaging consisted of a monoplane conventional C-arm X-ray system and a portable ultrasound machine using the usual guidewires and catheters for cardiovascular access. In this study, 30 patients, including 17 children younger than 2 years and 2 adults, underwent catheterization of the following cardiac anomalies: patent ductus arteriosus (20 patients) and pulmonary valve stenosis (9 patients, including 2 patients with critical stenosis and 3 patients with a secundum atrial septal defect). Except for two cases requiring surgery, the patients were treated successfully without complications. They all were discharged from hospital, usually the day after cardiac catheterization, and showed significant clinical improvement in the follow-up evaluation. Cardiac catheterization can be performed safely and very effectively in a country with limited resources. If patients are well selected, this mode of treatment is possible without the support of a sophisticated catheterization laboratory.

Eighteen-month outcome of pulmonary valve stent implantation by direct right ventricle puncture: an animal study

OBJECTIVE

The purpose of this study was to investigate the feasibility and safety of pulmonary valve implantation via direct right ventricle puncture.

METHODS

A standard thoracotomy and direct right ventricle puncture were performed in 8 healthy sheep to implant the pulmonary valve stents. Animals were followed up for 18 months.

RESULTS

Three sheep died within the first 4 months after stent placement. The remaining 5 animals survived. After 18 months, examinations by color echocardiography, 64-slice computed tomography scan, and cardiac catheter showed an ideal position of each stent. The function of the pulmonary valves and hearts was not different compared with the preoperative conditions of the sheep. Anatomic examination revealed that the stent was covered by a layer of endothelial tissue with no stent fracture or valvular calcification. The histologic evaluation of the stent and surrounding tissue showed that the surface of the stent was smooth and covered by a complete layer of endothelial cells without obvious infiltration of inflammatory cells. The vascular wall was integrative without tear phenomenon in each layer of tissue.

CONCLUSIONS

These results show that pulmonary valve stents can be implanted via direct right ventricle puncture. Further studies evaluating xenograft valve material and the effect of implantation in vivo are needed.

Transapical aortic valve replacement under real-time magnetic resonance imaging guidance: experimental results with balloon-expandable and self-expanding stents

OBJECTIVE

Aortic valves have been implanted on self-expanding (SE) and balloon-expandable (BE) stents minimally invasively. We have demonstrated the advantages of transapical aortic valve implantation (tAVI) under real-time magnetic resonance imaging (rtMRI) guidance. Whether there are different advantages to SE or BE stents is unknown. We report rtMRI-guided tAVI in a porcine model using both SE and BE stents, and compare the differences between the stents.

METHODS

A total of 22 Yucatan pigs (45-57 kg) underwent tAVI. Commercially available stentless bioprostheses (21-25 mm) were mounted on either BE platinum-iridium stents or SE-nitinol stents. rtMRI guidance was employed as the intraoperative imaging. Markers on both types of stents were used to enhance visualization in rtMRI. Pigs were allowed to survive and had follow-up MRI scans and echocardiography at 1, 3, and 6 months postoperatively.

RESULTS

rtMRI provided excellent visualization of the aortic valve implantation mounted on both stent types. The implantation times were shorter with the SE stents (60 ± 14s) than with the BE stents (74 ± 18s), (p=0.027). The total procedure time was 31 and 37 min, respectively (p=0.12). It was considerably easier to manipulate the SE stent during deployment, without hemodynamic compromise. This was not always the case with the BE stent, and its placement occasionally resulted in coronary obstruction and death. Long-term results demonstrated stability of the implants with preservation of myocardial perfusion and function over time for both stents.

CONCLUSIONS

SE stents were easier to position and deploy, thus leading to fewer complications during tAVI. Future optimization of SE stent design should improve clinical results.

Early and midterm hemodynamics after aortic valve bypass (apicoaortic conduit) surgery

BACKGROUND

Aortic valve bypass (AVB [apicoaortic conduit]) relieves aortic stenosis (AS) by connecting the apex of the left ventricle to the descending thoracic aorta with a valved conduit. AVB is performed through a small left thoracotomy, without cardiopulmonary bypass, aortic cross-clamping, cardiac arrest, or debridement of the native aortic valve. Little is known about hemodynamics, including ventricular performance, relative conduit blood flow, and progression of native AS after AVB.

METHODS

Forty-seven very high risk patients underwent AVB for AS between 2003 and 2009. The mean age was 82 years. Predismissal and interval transthoracic quantitative two-dimensional and Doppler echocardiography was performed in a core laboratory.

RESULTS

No patient had obstruction of the native aortic valve or the conduit during follow-up. The AVB effectively relieved left ventricular outflow tract obstruction (average peak gradient across the conduit was 5.6 +/- 3.8 mm Hg). Native aortic valve stenosis did not progress after AVB (0.63 +/- 0.16 cm(2) before surgery to 0.7 +/- 0.24 cm(2) at latest follow-up more than 6 months; p = 0.16). Total stroke volume increased after AVB from 60 mL +/- 22 mL to 107 mL +/- 27 mL (p < 0.0001). Left ventricular outflow was distributed in a predictable fashion between the conduit and the native aortic valve, with 63% +/- 10% of the flow directed to the conduit. Relative conduit flow remained stable (68% +/- 8%) at latest follow-up more than 6 months (p = 0.17).

CONCLUSIONS

Aortic valve bypass effectively relieves the outflow tract obstruction of AS. Placement of an apical valved conduit halts the biologic progression of AS.

Percutaenous mitral valve: A non-stented coronary sinus device for the treatment of functional mitral regurgitation in heart failure patients

Functional mitral regurgitation in heart failure limits survival in a severity-graded fashion. Even mild mitral regurgitation doubles mortality risk. We report the use of a non-stented coronary sinus device to reduce mitral annulus dimension in order to re-establish mitral valve competence. The device (PTMA, Viacor, Inc., Wilmington, MA, USA) consists of a multi-lumen PTFE (Teflon) PTMA catheter in which Nitinol (nickel-titanium alloy) treatment rods are advanced. For individual use up to three rods of different length and stiffness can be used. Therefore dimension reduction can be performed in an incremental fashion. Fluoroscopy and 3 D echocardiography are performed throughout the procedure to visiualize the positioning and confirm maximum treatment effect. The case describes the use and the effect of PTMA treatment. Safety and efficacy of the PTMA device will be investigated in the upcoming PTOLEMY 2 trial.

Transcatheter aortic valve implantation: the state of play

Aortic stenosis is the most commonly acquired valvular heart disease in the Western world. Surgical aortic valve replacement is currently the gold-standard treatment for patients with severe symptomatic aortic stenosis. Without surgery, the prognosis is extremely poor, with a 3-year survival rate of less than 30%. Transcatheter aortic valve implantation (TAVI) is a rapidly evolving novel technique that was first introduced in 2002 and is currently available in Europe as an alternative to conventional aortic valve replacement for patients with severe symptomatic aortic stenosis who are deemed to be at too high a risk for open heart surgery. This article describes the TAVI technique and patient selection criteria. We explore how far we have come with advances in TAVI and analyze the short- and medium-term outcome data reported on TAVI so far. We will also look at the potential future role of TAVI and the challenges involved in setting up a TAVI service.

Surgical revision after percutaneous mitral repair with the MitraClip device

BACKGROUND

Percutaneous mitral repair with the MitraClip device (Evalve, Menlo Park, CA) has been reported. Preserving conventional surgical options in the event of percutaneous treatment failure is important. We describe surgical treatment at varying intervals after the MitraClip procedure in 32 patients.

METHODS

One hundred seven patients with moderate-to-severe or severe mitral regurgitation who were either symptomatic (91%) or, if asymptomatic (9%), had evidence of left ventricular dysfunction were enrolled as part of the Endovascular Valve Edge-to-Edge REpair STudy (EVEREST) phase I registry study or as "roll-in" subjects in the EVEREST II study. Thirty-two of the 107 patients (30%) underwent surgery after an attempted MitraClip procedure.

RESULTS

Of the 32 patients undergoing post-clip mitral valve surgery, 23 patients (72%) had one or more clips implanted and 9 patients (28%) received no clip implant. The indications for mitral valve surgery in the 23 patients with a clip included partial clip detachment (n = 10), residual or recurrent mitral regurgitation greater than 2+ (n = 9), and other (atrial septal defect [n = 2], device malfunction [n = 1], and incorrectly diagnosed mitral stenosis [n = 1]). Twenty-seven of 31 patients (87%) underwent the surgical procedure planned before surgery (planned procedure unknown in 1 patient). Four of 25 patients (16%) with planned repair underwent mitral valve replacement.

CONCLUSIONS

Standard surgical options were preserved in patients who had surgery after percutaneous repair with the MitraClip device. Successful repair was feasible in the majority of patients after the MitraClip procedure, with repair performed as late as 18 months after clip implantation.

Neuro-kardio-fazio-kutane Syndrome

Neuro-kardio-fazio-kutane („neuro-cardio-facio-cutaneous“: NCFC) Syndrome wurden in den letzten Jahren als eine Gruppe von angeborenen Erkrankungen definiert, deren phänotypische Überschneidungen eine gemeinsame pathogenetische Grundlage haben. Erkrankungen aus diesem phänotypischen Spektrum gehen mit einer Überfunktion des RAS-MAPK-Signalwegs (RAS: „rat sarcoma“, MAPK mitogenaktivierte Proteinkinase) einher. Zu den neuro-kardio-fazio-kutanen Erkrankungen gehören das Noonan-, das LEOPARD-, das kardio-fazio-kutane („cardio-facio-cutaneous“: CFC) und das Costello-Syndrom, die Neurofibromatose Typ 1 sowie das Legius-Syndrom. Für eine sachgerechte medizinische Diagnostik und Behandlung sowie die notwendige psychosoziale Betreuung von Betroffenen und deren Familien ist das Zusammenwirken verschiedener Fachdisziplinen notwendig.

[Percutaneous mitral annuloplasty with the VIACOR coronary sinus system for the treatment of functional mitral regurgitation in heart failure patients. Development and results]

Functional mitral regurgitation (MR) in heart failure patients limits survival in a severity-graded fashion. Even mild MR doubles the mortality risk. The use of a nonstented coronary sinus device to reduce mitral annulus dimension in order to reestablish mitral valve competence is reported. The device (PTMA, Viacor, Inc., Wilmington, MA, USA) consists of a multilumen PTFE (Teflon) PTMA catheter in which nitinol (nickel-titanium alloy) treatment rods are advanced. For individual treatment, up to three rods of different length and stiffness can be used. Therefore, dimension reduction can be performed in an incremental fashion. Fluoroscopy and three-dimensional (3-D) echocardiography are performed through the procedure to visualize the positioning and confirm maximum treatment effect. This report describes an implant case and summarizes the safety and feasibility of the new PTMA treatment device in 27 patients. The cases reflect the learning curve in both device design and implantation technique. In permanent implant, a sustained reduction of mitral annulus septal-lateral dimension from 3-D echo reconstruction dimensions was observed (4.9 +/- 1.2 mm at 3 months).

Percutaneous reimplantation of a pulmonary valved stent in sheep: a potential treatment for bioprosthetic valve degeneration

OBJECTIVE

Percutaneous pulmonary valve replacement has been recently introduced into clinical practice. Patients with transcatheter pulmonary valve replacement will definitely face the problems of valve degeneration. In addition to surgical re-replacement of the degenerated bioprosthetic valves, we studied the replacement of degenerated bioprosthetic valves with transcatheter reimplantation of stent-mounted pulmonary valves.

METHODS

Percutaneous pulmonary valve replacement was first performed in 6 sheep used a homemade valved stent. Two months after the initial procedure, the 6 sheep previously implanted with a valved stent underwent the same implantation procedure of a pulmonary valved stent. Hemodynamic assessment of the bioprosthetic pulmonary valve was obtained by echocardiography immediately post-implant and at 2 months follow-up.

RESULTS

All 6 sheep had successful transcatheter stent-mounted pulmonary valve replacement in the first experiment. After 2 months, reimplantation was successful in 5 sheep but failed in 1 sheep because the first valved stent was pushed to the bifurcation of the pulmonary artery by the delivery sheath. Echocardiography confirmed the stents were in the desired position during the follow-up. The remaining 5 sheep with normal valvular and cardiac functionality survived for 3 months after implantation.

CONCLUSION

Transcatheter stent-mounted bioprosthetic pulmonary valve reimplantation is feasible in an animal model and more convenient than open chest reimplantation.

Percutaneous Transvenous Mitral Annuloplasty

Background— We assessed the safety and feasibility of permanent implantation of a novel coronary sinus mitral repair device (PTMA, Viacor Inc).

Methods and Results— Symptomatic (New York Heart Association class 2 or 3) patients with primarily functional mitral regurgitation (MR) were included. A diagnostic PTMA procedure was performed in the coronary sinus venous continuity. MR was assessed and the PTMA device adjusted to optimize efficacy. If MR reduction (≥1 grade) was observed, placement of a PTMA implant was attempted. Implanted patients were evaluated with echocardiographic, quality of life, and exercise capacity metrics. Nineteen patients received a diagnostic PTMA study. Diagnostic PTMA was effective in 13 patients (MR grade 3.2�0.6 reduced to 2.0�1.0), and PTMA implants were placed in 9 patients. Four devices were removed uneventfully (7, 84, 197, and 216 days), 3 for annuloplasty surgery due to observed PTMA device migration and/or diminished efficacy. No procedure or device-related major adverse events with permanent sequela were observed in any of the diagnostic or implant patients. Sustained reductions of mitral annulus septal-lateral dimension from 3D echo reconstruction dimensions were observed (4.0�1.2 mm at 3 months).

Conclusions— Percutaneous implantation of the PTMA device is feasible and safe. Acute results demonstrate a possibly meaningful reduction of MR in responding patients. Sustained favorable geometric modification of the mitral annulus has been observed, though reduction of MR has been limited. The PTMA method warrants continued evaluation and development.

Effect of percutaneous mitral repair with the MitraClip device on mitral valve area and gradient

AIMS

Percutaneous repair of mitral regurgitation (MR) by leaflet apposition using a clip deployed via transseptal catheterisation is undergoing evaluation.

METHODS AND RESULTS

In order to detect the potential for clinically significant left ventricular inflow obstruction after percutaneous repair, we measured mitral valve area (MVA) and mean transmitral gradient (MVG) echocardiographically in 96 patients implanted with a clip followed for up to 24 months. By planimetry, the mean MVA decreased from 6.0 +/- 1.3 cm2 to 3.6 +/- 1.2 cm2 (p < 0.05) (range 1.9 to 7.6 cm2) after clip placement, and remained unchanged after 24 months of follow-up (3.5 +/- 0.8 cm2). The mean MVG increased after clip placement from 1.7 +/- 0.9 mmHg to 4.1 +/- 2.2 mmHg (p < 0.05), and did not increase further to 24 months (3.8 +/- 1.9 mmHg). There were no differences in MVA or MVG between patients who received 1-clip (69%) and those receiving 2-clips (31%). Patients with functional MR (23%) had a slightly smaller MVA, both at baseline and after clip placement, but did not differ from degenerative MR patients at later follow-up. After 2 years of follow-up, no patient required surgery for LV inflow obstruction.

CONCLUSIONS

Mitral repair with the MitraClip device for MR decreases MVA without significant mitral obstruction. After 2 years of follow-up, no patient required surgery for LV inflow obstruction, and these results were not influenced by the use of more than 1 clip or the aetiology of MR.

Distinct but parallel evolutionary patterns between alcohol and aldehyde dehydrogenases: addition of fish/human betaine aldehyde dehydrogenase divergence

Alcohol dehydrogenases (ADHs) of the MDR type (medium-chain dehydrogenases/reductases) have diverged into two evolutionary groups in eukaryotes: a set of 'constant' enzymes (class III) typical of basal enzymes, and a set of 'variable' enzymes (remaining classes) suggesting 'evolving' forms. The variable set has larger overall variability, different segment variability, and variability also in functional segments. Using a major aldehyde dehydrogenase (ALDH) from cod liver and fish ALDHs deduced from the draft genome sequence of Fugu rubripes (Japanese puffer fish), we found that ALDHs form more complex patterns than the ADHs. Nevertheless, ALDHs also group into 'constant' and 'variable' sets, have separate segment variabilities, and distinct functions. Betaine ALDH (class 9 ALDH) is 'constant,' has three segments of variability, all non-functional, and a limited fish/human divergence, reminiscent of the ADH class III pattern. Enzymatic properties of fish betaine ALDH were also determined. Although all ALDH patterns are still not known, overall patterns are related to those of ADH, and group separations may be distinguished. The results can be interpreted functionally, support ALDH isozyme distinctions, and assign properties to the multiplicities of the ADH and ALDH enzymes.