**4.4 Durability and cost**

*Advances in Complex Valvular Disease*

There is a common misconception that trans-catheter therapies are inherently associated with fewer strokes. This is an observation that has not been demonstrated in many of the high-profile studies. Furthermore, there are growing concerns that the neurologic events that patients experience after trans-catheter therapies occur after the index hospitalization in which the procedure is performed. For example, one study exploring a Medicare database of over 44,000 patients suggested an 86% greater risk of ischemic stroke and a six-fold increase risk of hemorrhagic stroke after trans-catheter therapies when compared to conventional surgery, with many of the events occurring in subsequent readmissions to the hospital within the first year [19]. In fact, the 90-day readmission rate for neurologic events after TAVR was substantially higher than many other cardiac and non-cardiac procedures, including left ventricular assist device placement, cardiac catheterization, surgical aortic valve replacement, and coronary artery bypass procedures [20]. Clearly, the risk of neurologic events after catheter-based valvular interventions requires further

Such concerns have resulted in a substantial increase in the development and utilization of cerebral protection devices during TAVR. Despite the inherent appeal and considerable cost associated with these protection devices, definitive data demonstrating a clinical improvement and reduction in neurologic events is still lacking [21, 22]. Nevertheless, this is an area of tremendous research and

There is no doubt, as demonstrated in almost every major study of TAVR, that this procedure is associated with a much greater risk for needing a permanent pacemaker when compared to conventional surgery. While conduction abnormalities are not uncommon after valve surgery, there is growing concern that the need for a pacemaker after TAVR is neither trivial nor benign. Some large-scale studies suggest a four-fold increase in the need for permanent pacemaker after TAVR [25]. While the long-term consequences of needing a pacemaker are still unclear, especially since the short and long-term natural history of conduction problems after valve replacement is variable, there is evidence to suggest that the need for a pacemaker is associated with worse long-term survival in these patients [26]. Considering the growing emphasis on early discharge and the concern that some of the conduction abnormalities might be physiologically significant and not present until after the index hospitalization, the consequences of such events is still

Unlike surgical valve replacement in which the existing stenotic calcified valve is physically removed, TAVR inserts and expands against the existing valve. This fundamental difference in the two procedures can explain why TAVR is still associated with a significantly higher rate of paravalvular leaks – especially in those with eccentric valve pathology or bicuspid valves [28]. Again, the long-term significance of paravalvular leaks is incompletely defined, but without a doubt, those patients with at least moderate leaks have a much worse survival at 2 years than those with mild or less leaks. The PARTNER 2 study, as previously discussed

**4. Evolving controversies**

**4.1 Stroke**

objective review.

development [23, 24].

**4.2 Pacemaker rates**

unclear [27].

**4.3 Paravalvular leaks**

**6**

Durability and cost remain a considerable concern regarding catheter-based therapies. Although costs vary significantly depending on the intrinsic structure of a health-care system, conflicting evidence regarding the short- and long-term costs of different types of therapy for valvular disease exists. Without a doubt, a surgical valve is substantially less expensive than a catheter-based valve, but the overall costs of the hospitalization and short-term rehabilitation needs might be more. However, factoring in the needs for pacemakers, stroke management, and concomitant coronary disease, there is growing concern surrounding the real-world costs for catheter-based therapies – especially as an increasing number of patients with advanced comorbidities, age, and poor functional status are being treated prior to dying [30, 31].

### **4.5 Coronary artery interventions**

Especially with patients who are older and have multiple comorbidities, the incidence of coronary artery disease further challenges clinical decision-making. Again, despite the appeal of catheter-based solutions to treat both obstructive coronary disease and aortic valve pathology, definitive data directing one therapeutic option over another is lacking. In fact, many of the initial studies exploring the outcomes of one approach over another specifically excluded concomitant coronary procedures or those patients with significant obstructive disease. Nevertheless, criticism of some of the more recent low risk trials is that the surgical patients had a much higher intrinsic risk profile because of the need for concomitant coronary revascularization. In addition, structural characteristics of artificial valves also raises concerns regarding difficulties in coronary access in patients with previous valve replacements (both surgical and TAVR) and further suggests the importance of complete revascularization at the time of definitive valve therapies. As mentioned, many studies specifically excluded patients with combined aortic stenosis and coronary artery disease, and current guidelines tend to favor surgery considering the limitations of the data [32, 33]. Preliminary data also suggests that patients undergoing coronary stenting prior to TAVR may have worse outcomes and increased need for re-interventions due to major adverse cardiac and cerebrovascular events [34, 35].

### **4.6 Repeat interventions**

The area of aortic valve disease that probably is the most supportive of transcatheter therapies is in patients that have had previous valve replacement, either with a previous surgical valve or a trans-catheter valve. Many patients underwent surgical replacement with a biologic valve, despite established guidelines and a potential survival advantage advocating the use of a mechanical valve under the promise that their next intervention would be a trans-catheter valve [36, 37]. While the appeal of this approach is undeniable and logical, the practical applications are still under considerable study. Conflicting data regarding the best approach for the management of a failing biologic valve is substantial. Even though repeat surgery is not without risks, many experienced centers can offer re-operative surgery with a risk profile similar to first-time valve replacement. Furthermore, there are concerns surrounding a reduction in the effective orifice areas and the risk for patientprosthesis mismatch after placement of a TAVR inside of a previous surgical or trans-catheter valve.

## **4.7 Choice of valves**

In the surgical era, the choice of valves consisted of tissue valves and mechanical valves. Mechanical valves required life-long anticoagulation and this was often unappealing to patients, despite studies demonstrating a long-term survival advantage. Tissue valves did not require long-term anticoagulation, but were associated with structural degeneration and the need for repeat interventions – often at significant risk as outlined above. Many different types of biologic valves exist – bovine, porcine, homographs, stentless, etc – and there is extensive literature generated over decades of experience regarding the advantages and disadvantages of each valve type. Much of the decision-making regarding the initial valve choice is now under debate with the development of catheter-based therapies that can be used for failing biologic valves. Since the concept (as mentioned above) of "valve-in-a-valve" has altered the natural history of the long-term outcomes associated with biologic valves, there is growing interest in their use in younger patients and in the use of those prosthetic valves with structural characteristics that might lend themselves to a more favorable scaffolding for future re-interventions. Concepts surrounding strut design and annular cracking (or fracking) to increase the annular size to allow for larger replacement valves are rapidly evolving areas of study [38]. Likewise, the choice of transcatheter valve design – annular, supra-annular, self- vs balloon-expanding - and tissue characteristics are also areas of extensive clinical research and debate.

### **4.8 Indications for intervention**

The guidelines for intervention on critical aortic stenosis have also been evolving to reflect the developments in therapy options. However, there is growing evidence to suggest that adverse, and potentially irreversible, structural changes in the myocardium occur prior to the development of symptoms. Even patients with very advanced disease can have minimal symptoms, and much research is being directed towards, as illustrated by the chapter on strain-rate assessment of valvular disease, more objective tools to assess the pathophysiologic consequences of valvular pathology. Tools such as cardiac magnetic resonance imaging, strain-rate, and stressechocardiography are becoming more commonly used in complex clinical cases to help direct management decisions.

### **4.9 Other areas of debate**

The list of potential controversial topics in the diagnosis and management of valvular disease is extensive and beyond the scope of a simple chapter or even text. Such areas only illustrate the complexity of valve disease and, especially in the context of newer options for therapy, how there are great opportunities to reexplore the options patients have for aortic valve interventions. Even the methods we have to guide therapies – such as the development of Heart Teams (similar to cancer tumor boards in which each patient's clinical characteristics and pathologies are reviewed to make an optimal decision based upon expertise and best available data) and "shared decision making" (a concept in which the patient plays a substantial role in deciding how they want to be treated after weighing the pros/cons of the options as presented to them) – continue to evolve [39].

**9**

*Introductory Chapter: The Evolution of Complex Valve Pathology - The Surgeon's Perspective*

Other areas that only scratch the surface regarding the management of valve

*DOI: http://dx.doi.org/10.5772/intechopen.95049*

○ Native vs prosthetic valve

○ Early vs late surgical vs medical management

○ Indications for left-sided vs right-sided valves

• Associated ascending aortic aneurysms and pathology

○ Re-operative options in the setting of substance abuse

disease include:

• Endocarditis

• Aortic insufficiency

○ Timing of surgery

• Bicuspid valve disease

○ Role of catheter-based therapy

• Impact of previous cardiac surgery

○ End-stage renal disease – i.e. dialysis

• Special patient populations

○ Small/large aortic roots

○ Complex co-morbidities

○ Women of child-bearing age

○ Impact of other co-morbidities

2.End-stage pathologies – i.e. liver, lung, cancers

○ Risk for tissue or valve degeneration/thickening

• Role of anticoagulation/anti-platelet agents

○ Impact on short-term risk for stroke

○ "Younger" patients

1.Frailty

3.Age

○ Morbid obesity

*Introductory Chapter: The Evolution of Complex Valve Pathology - The Surgeon's Perspective DOI: http://dx.doi.org/10.5772/intechopen.95049*

Other areas that only scratch the surface regarding the management of valve disease include:

• Endocarditis

*Advances in Complex Valvular Disease*

**4.8 Indications for intervention**

help direct management decisions.

options as presented to them) – continue to evolve [39].

**4.9 Other areas of debate**

trans-catheter valve.

**4.7 Choice of valves**

surrounding a reduction in the effective orifice areas and the risk for patientprosthesis mismatch after placement of a TAVR inside of a previous surgical or

In the surgical era, the choice of valves consisted of tissue valves and mechanical valves. Mechanical valves required life-long anticoagulation and this was often unappealing to patients, despite studies demonstrating a long-term survival advantage. Tissue valves did not require long-term anticoagulation, but were associated with structural degeneration and the need for repeat interventions – often at significant risk as outlined above. Many different types of biologic valves exist – bovine, porcine, homographs, stentless, etc – and there is extensive literature generated over decades of experience regarding the advantages and disadvantages of each valve type. Much of the decision-making regarding the initial valve choice is now under debate with the development of catheter-based therapies that can be used for failing biologic valves. Since the concept (as mentioned above) of "valve-in-a-valve" has altered the natural history of the long-term outcomes associated with biologic valves, there is growing interest in their use in younger patients and in the use of those prosthetic valves with structural characteristics that might lend themselves to a more favorable scaffolding for future re-interventions. Concepts surrounding strut design and annular cracking (or fracking) to increase the annular size to allow for larger replacement valves are rapidly evolving areas of study [38]. Likewise, the choice of transcatheter valve design – annular, supra-annular, self- vs balloon-expanding - and tissue characteristics are also areas of extensive clinical research and debate.

The guidelines for intervention on critical aortic stenosis have also been evolving to reflect the developments in therapy options. However, there is growing evidence to suggest that adverse, and potentially irreversible, structural changes in the myocardium occur prior to the development of symptoms. Even patients with very advanced disease can have minimal symptoms, and much research is being directed towards, as illustrated by the chapter on strain-rate assessment of valvular disease, more objective tools to assess the pathophysiologic consequences of valvular pathology. Tools such as cardiac magnetic resonance imaging, strain-rate, and stressechocardiography are becoming more commonly used in complex clinical cases to

The list of potential controversial topics in the diagnosis and management of valvular disease is extensive and beyond the scope of a simple chapter or even text. Such areas only illustrate the complexity of valve disease and, especially in the context of newer options for therapy, how there are great opportunities to reexplore the options patients have for aortic valve interventions. Even the methods we have to guide therapies – such as the development of Heart Teams (similar to cancer tumor boards in which each patient's clinical characteristics and pathologies are reviewed to make an optimal decision based upon expertise and best available data) and "shared decision making" (a concept in which the patient plays a substantial role in deciding how they want to be treated after weighing the pros/cons of the

**8**

	- Timing of surgery
	- Role of catheter-based therapy
	- End-stage renal disease i.e. dialysis
	- Morbid obesity
	- Small/large aortic roots
	- Complex co-morbidities
	- "Younger" patients
	- Women of child-bearing age
	- Impact of other co-morbidities
		- 1.Frailty
		- 2.End-stage pathologies i.e. liver, lung, cancers

3.Age

	- Impact on short-term risk for stroke
	- Risk for tissue or valve degeneration/thickening
	- Atrial fibrillation
	- Obstructive coronary artery disease
	- Other valvular pathologies
		- 1.Mitral, tricuspid
	- Aortic aneurysms
	- Bovine vs porcine vs non-biologic
	- Anti-calcification treatments
	- Stented vs non-stented
	- Stent material
